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FAQs on Magnesium in Seawater

Related Articles: Magnesium (Mg) and its Role in the Reef Aquarium by James Gasta,

Related FAQs:  Calcium and Alkalinity

The best source of alkaline earth biominerals... "melted down" coral rubble.

Hi Bob, 

I've been trying to keep my levels as stable as possible using only water changes and adding liquid magnesium (as this seems to be the main parameter I struggle to keep up) I'm using D-D H20 salt and do 15% water changes of around 50 litres per week. But, I'm still finding that most weeks my kH drops by 1 (it's usually 9 after a water changes then 8 by the end of the week but sometimes drops slightly below 8) I'm reluctant to use buffers, as I know that it isn't sustainable as it could lead to my kH rising gradually.

I've been exploring balling lite but I'm still a bit perplexed by how to dose and I was never really very good at chemistry!
Would a calcium reactor help keep everything even or will it just maintain just calcium? I do add coral grower and trace elements weekly but am I doing enough to keep everything stable?

Thanks in advance
Katie Advani  

Salve Katie. Might I ask how you are adding to your Mg? Simple Epsom Salt (Magnesium Sulfate, MgSO4) addition is my fave'¦ for being inexpensive, effective and readily available. Next, the loss of KH, dKH can be due to a few circumstances'¦ most often due to livestock metabolism, uptake by biomineralizing life. In essence, overall processes in captive systems are reductive, acidic, with loss of alkalinity a common affair. And corals, calcareous algae and more can really use up a good deal of alkaline reserve (along with Calcium, Magnesium'¦), particularly in brightly lit, over-driven settings. You don't mention your livestock and/or feeding practices, but these may be an important part of the puzzle here, as might be inefficient skimming.            

            I'm a bit confused re your reluctance to utilize a commercial buffer. I definitely would read up, employ one myself'¦ Best dissolved into new/make up water for when you do your weekly maintenance. I want to help you set aside your worries here re simple chemistry. You mention the use of a 'coral grower' and some supplements; I encourage you to spend some time with your in-print works and the internet reviewing the listed active ingredients, their interactions. Again, I would be using an 'all in one' (carbonate, bicarbonate'¦) buffer if this were my system. 

            Concerning the question of use of a calcium reactor, depending on the media you're using, melting down, mostly Calcium and Carbonate will be provided. There are some products that will also generate free Magnesium. IF you have a large system (hundreds of gallons) and/or a good deal of valuable biomineralizing life (e.g. stony corals) a calcium reactor might be worth considering. However, I'd gain a basic understanding, working of the system without one first.

High magnesium        7/6/15
Hello WWM Crew,
I have been a follower of your site for many years now and have learned so much from the dedicated people of WWM, thanks so much. I have a problem with high magnesium and I searched the site and the only solution I found doesn’t apply to my situation. My magnesium is testing at 1500 with a Salifert kit while my calcium is 395/400. My other parameters are Sg 1.026, Ph 8.3, DKH 9, Nitrites 0, Nitrates minimal. The answer I found was to do water changes which was my first instinct.
<Usually does it>
My problem is I have two 20g trash cans with aged, aerated and heated salt water that also tests at 1500.
<Mmmm... strange; salt brand?>

I thought it was my test kit so I went out and bought a new one that is good till 2018 and it also test the same. My salt mix has been Tropic Marin for the last 8 years but I have been slowly changing to Instant Ocean for dollar purposes. I live in Canada and Tropic Marine is $115.00 and Instant Ocean is $43.00. The only thing I can think of that would maybe raise my Mg in my new mix is that I buffer my R/O D/I water with a teaspoon of Seachem Marine Buffer to a 20g trash can before I salt, other than that I don’t use other additives. Would you have any other suggestions that I can try. Thanks again for this wonderful service you provide.
<Am more inclined to think it's the IO... they've had problems off/on. Your [Mg] isn't that far out of ratio though... t'were it me, mine, I'd use the current mixed water; look for another batch # for the buckets of IO. Bob Fenner>
Re: High magnesium        7/6/15

Hi Mr. Fenner,
Wow that was fast. Thanks so much I'll try that or I will stick with the TM.
<Real good Bri... again; your not alone with these sorts of issues. You can read re others here:
and elsewhere on WWM. Cheers, BobF>

Epsom salt treatment with high magnesium?     3/19/14
Hi Bob and Crew, I have been a follower of WetWebMedia for many years and have always found an answer in your extensive archives to my queries, until now. I have 2 chalk bass and one of them has developed PopEye in one eye only. As I saw the other one peck it near the eye a few days ago I assume this is the cause. After searching your web site I would like to follow the advice I found there and treat my MD with 1 tablespoon per 10 gallons with Epsom salts. However, this is my query/problem, I have high magnesium levels already. Its too long a story how this came about but I am convinced it was through using Reef Crystals sea salt to set up the tank because I had high readings for parameters i.e. alkalinity and calcium ( no magnesium test at first) right from the start! Now my readings are: Alk, now a bit low 7.8dKH,
<You could raise this up... to precipitate out the Alkaline earths (Ca, Mg)....>
pH 8.2, Ca 400ppm o.k. , and Mg 1600 way too high! The Mg was 1480 a couple of days ago but I dosed 1tsp Kalkwasser to raise dKH (then 7.1) and so that must be what raised the Mg
<Not... where would the Mg come from?>

because no other additives have been used! I have been doing regular weekly 10% water changes with instant ocean to try to get things back Into sync but not sure now how to get Mg readings down?
<See above. This or massive water change outs; replacing the water with that of less Magnesium>
Back to my PopEye problem, will adding Epsom salts make the Mg situation worse? what would you suggest?
<I would treat in the med. tank regardless; Not let the high Mg bother me>
I would be very grateful for any help you can offer and thanks again for such a useful and informative site! Jenny
<Welcome. Bob Fenner>
Re Epsom salt treatment with high magnesium?     3/20/14

Thanks Bob for speedy reply to message below, much appreciated!
I have inserted a couple more comments/questions, hope this is o.k.!
Hi Bob and Crew, I have been a follower of WetWebMedia for many years and have always found an answer in your extensive archives to my queries, until now. I have 2 chalk bass and one of them has developed PopEye in one eye only. As I saw the other one peck it near the eye a few days ago I assume this is the cause. After searching your web site I would like to follow the advice I found there and treat my MD with 1 tablespoon per 10 gallons with Epsom salts. However, this is my query/problem, I have high magnesium levels already. Its too long a story how this came about but I am convinced it was through using Reef Crystals sea salt to set up the tank because I had high readings for parameters i.e. alkalinity and calcium ( no magnesium test at first) right from the start! Now my readings are: Alk, now a bit low 7.8dKH,
<You could raise this up... to precipitate out the Alkaline earths (Ca, Mg)....> <<Think this is the way I will go with water changes as well, how high would you gradually go with Alkalinity rise?>>
<<A few dKH more... it won't stay... will precipitate out with the alkaline earths>>
pH 8.2, Ca 400ppm o.k. , and Mg 1600 way too high! The Mg was 1480 a couple of days ago but I dosed 1tsp Kalkwasser to raise dKH (then 7.1) and so that must be what raised the Mg
<Not... where would the Mg come from?><< Suggested this as all I could think of but looked on ingredients and see no mention of Mg so I am now stumped as to where it has come from!! Tested with RedSea titration but wonder if correct reading now!>>
<Me too; limewater; Kalk is Calcium Hydroxide... no Mg in it>

because no other additives have been used! I have been doing regular weekly 10% water changes with instant ocean to try to get things back Into sync but not sure now how to get Mg readings down?
<See above. This or massive water change outs; replacing the water with that of less Magnesium>
Back to my PopEye problem, will adding Epsom salts make the Mg situation worse? what would you suggest?
<I would treat in the med. tank regardless; Not let the high Mg bother me><< Do you mean main display here?
I couldn't catch the fish without tearing down the tank as he is small and many crooks and crannies in the reef! I read in archives its safe to dose Epsom salts at 1 tablespoon per 10 gallons, some say per 5 gallons, in main Display, do you still agree with this? Which dose should I use with my high Mg? Thanks so much for your help!>>
<<IF necessary in the main tank; yes. Trapping the Serranus, draining the tank down and removing most decor to remove it to isolation... may well be too stressful>>
I would be very grateful for any help you can offer and thanks again for such a useful and informative site! Jenny
<Welcome. Bob Fenner>
Epsom salt treatment with high magnesium (update)
... Plus move to Popeye, Epsom f's     3/23/14
Hello again Bob, thought you might like to know that the one dose (1 tablespoon per 10 gallons) of Epsom salts to my main Display has had the desired effect and my little chalk bass is making an amazing recovery from his, very bad PopEye (caused by the other little chalk bass)!
<Ah, good>
I am very grateful! As for the Magnesium problem, I have to admit I made a mistake testing! I used Redsea's test for the first time and my only excuse is that the diagrammatical instructions had a very small *5 printed outside the box which I didn't see, meaning I was 4 drops short of one of the chemical components used! My reading now is 1400 not 1500. Still high I know but not as scary! I am following your instructions to make this 3 times the calcium reading.
Once again thanks for your help and I will continue to use your brilliant archives as before. Jenny
<Thank you for this valuable follow-up. BobF> 

High Magnesium and Alkalinity Readings – 04/25/13
<<Hiya Tim>>
I have a 65 gallon tank with 20 gallon sump, my magnesium levels are running 1600 or slightly above and my alkalinity is running high at 14.
 <<14 dKH I assume>>
Wondering what to do to get them down even with water changes it is not coming down.
<<Test your “new” water before adding it to the tank to see if it has high readings like your tank.  If so…test your tap water to see if it’s the culprit, or if your salt mix is to blame.  If not…I recommend new/different test kits and/or take a sample to your LFS for comparison.  If none of this proves to be the problem, then it may well be the rock/substrate in your tank causing the elevated readings>>
 I have fish and corals. Please let me know what you think. Thank you Tim
Salinity 1.024
Calcium 420
Alkalinity 14
Nitrates 10
Nitrites 0
Ammonia 0
Ph 8.3
Temp 76
<<Happy to share…  EricR>>

Issues with reading the MagPro test kit/Test Kits 2/24/13
<Hello Pam>
Wow, do I have issues with reading the MagPro test kit for magnesium!
<I'll bet I know just what this is without looking further.>
I followed the directions, which really screw with my intelligence!
I feel the need to hang on every word to make sure I'm doing it correctly!
So, in the final step, when I'm using the titrant, and it turns from pink to blue, I'm suppose to measure the AMOUNT of titrant used, and then compare that number to get my total magnesium.
I start at 1.0ml of titrant. The plunger ends just short of 0.2ml.
Simple math would tell me my number is "8" with a total magnesium of 1600.
<Correct, it is.  The problem here is knowing when you see enough blue. 
You can easily add a few more drops and it will darken some, turn to purple, then to red.  The color chart usually does not show the same exact color blue you see in the test vial.  At best, accuracy is no better than 100ppm but we are measuring for drastic Mg drops here and/or an approximate average.  It doesn't hurt to be a couple hundred ppm over but no more.>
What messes with my reasoning is the directions in the beginning. With the position of the plunger (at 1.0) while the water <titrant> is below that number.
<This is common but we are measuring the amount used based on where the plunger is when you see blue.  I put the titrant in a narrow test tube and then draw the titrant into the syringe making sure that the top area between the tip and the syringe is below the titrant level in the test tube.  This eliminates some of the air being drawn into the syringe. 
Whatever titrant remains in the test tube can be put back into the titrant container.>
Hmmm, now that I've talked through this, I do believe I'm understanding it.
But I'm going to send this query along, just in case someone out there has been as intimidated as I with this test kit!
<If you really want to be intimidated, try learning Adobe Photoshop Elements.  It's on my shelf now and out of the computer until I buy a copy of Photoshop Elements for Dummies. :-))>
Thanks for your input!
<You're welcome.  James (Salty Dog)>
Re Issues with reading the MagPro test kit/Test Kits 2/24/13

Hahahha!!! I hear ya on the Adobe!! Ouch, my brain!!!
Thanks for your input with the Mag test, too. I'll add more drops next time to see when it turns purple, then red.
<Yes, keep track of how much more it takes to turn red.  Example, test turns blue with .5 titrant used and then red with .7 titrant used, then in future tests you could add another .1 after it turns blue.  You will at least get some consistency doing it that way.  As to the Adobe, it's likely more program than what I really need.  Got a good price on it so I got it.
James (Salty Dog)>
Re Issues with reading the MagPro test kit/Test Kits 2/25/13

I'm smiling  :)
<Great, glad we could help you out Pam.  James (Salty Dog)>

High Magnesium and Turbo Snails    2/4/13
Hello crew, hope you are well. I've written several times before about my inability to keep Turbo Snails alive in my hair-algae-infested 29 gallon FOWLR tank. I'm still having the problem. My magnesium reads at 1500 ppm or slightly above with my Salifert kit. I've seen statements that magnesium is a muscle relaxant for snails.
<Yes... for most all animals>
 They die within a week or so, and do seem to fall down a lot before they succumb. I've tried Instant Ocean and Tropic Marin salts lately, and the newly-mixed saltwater always tests at 1500 or above.
<Strange. You want it, [Mg], to be about three times the concentration of Calcium>
I went to a good fish store today, and they confirmed the 1500 magnesium reading. They said this was surprising, since salt mixes generally produces less magnesium than this (especially Instant Ocean).
They suggested the extra magnesium may be coming from my water source (RO, but not DI).
<Mmm, nah>
I tried to test for magnesium in my RO water, but the Salifert Mg test kit doesn't seem to work with fresh water. So my questions: is this magnesium level (with a calcium level generally between 400 and 450) capable of killing turbo snails in a couple of weeks?
<Yes; it can>
(Other inverts, such as Margarita Snails and Fire Shrimp, seem to do OK in the tank.) Is it likely for 100 to 200 ppm of magnesium to pass through my RO filter?
 Is there a way I can test for it (i.e. a test that works in fresh water)?
<There are... you might look on Hach and LaMotte's websites... or a lab nearby or distal that you can send a sample to for testing>
I don't want to buy a DI filter without a good reason. Thanks, Jerry
<Welcome. Please do report back to us w/ your further findings. Bob Fenner>

Very High Calcium and Magnesium Levels. Why and How to Fix? and a Big Upgrade to the Sump/Refugium/Return. Should I Go Through With It?     10/4/12
Hello there!  Thank you in advance for all your help and what you guys do.  I have a few questions regarding high Calcium and Magnesium levels in my aquarium and a few questions regarding an upgrade I want to do with my system.  I will begin by giving you an outline of my system and other info that may need to be known to answer some of my questions. Sorry if I am overly detailed but I figure more info is better than not enough.
 I have a reef ready (built in overflow) Oceanic 75 gallon aquarium set up as a mixed reef tank (I want it to be heavy SPS though).

The tank has been up and running for a little over 7 months now.  For filtration: Aqueon Proflex sump model 2 (roughly 20 gallons), AquaC-EV 180 protein skimmer, water passes through a sponge in sump (included with setup), two 200 micron filter socks (also included with setup), roughly 80lbs dry rock from Bulk Reef Supply (mix of Pukani, Fiji, Tonga branch, reef saver), 80 lbs. Carib Sea's Special Grade Reef Sand (dead and 1.0-2.0mm) and two reactors.  My reactors are from Bulk Reef Supply.  I have two single deluxe reactors which is run by one pump: MJ1200. This pump is located in the third chamber if the sump and is output in the refugium or second chamber.  In one reactor I run BRS GFO high capacity and BRS premium ROX 0.8 Carbon. No matter what I change the Carbon media every 2 weeks and the GFO media every 4 weeks. I also have a refugium in the sump.
Aqueon Proflex sumps have several different ways you can set them up so I chose the refugium style although I set mine up differently than the way they recommended.  In mine I have my protein skimmer pump (Mag Drive 7) located in the first chamber of the sump right below the filter socks.  I set the protein skimmer in the third and last chamber in the sump which outputs the water in the bubble trap area (area where the sponge is located and where water flows from the refugium to the third chamber).  To accomplish this I just screwed in a small piece of PVC piping with a 45 degree angle PVC piece on the end into the gate valve piece/output of the skimmer.  The skimmer is also raised about 3 inches using cut egg crate pieces stacked on top of each other using zip-ties.  This actually brings the skimmers output right to or slightly above the water level which is what is recommended in the skimmer manual.  Outputting in this area helps reduce bubbles created by the skimmer.  I made this "customization" because I wanted to skim the water that first enters the sump before going to the refugium.  I didn't want the water that comes from the fuge, which should often include beneficial bacteria/life such as pods and other things, to be skimmed before going to the display as that could kill that beneficial life.  In my refugium I have 1.5 inches of miracle mud as the substrate, 2 pretty large pieces of rock, some rock rubble, and a big ball of Chaetomorpha.  I have a simple PC light hanging above the fuge which I run all the time 24/7.  Inside the fuge I also have 2 heaters: two Finnex HMA-150 watt w/analog control.  These are side by side.
                My return process is a little confusing.  I use 2 return pumps: Danner Mag Drive 7 and an Iwaki MD-30RXLRT. The Mag 7 is located in the third chamber.  The Iwaki is located just outside the sump to the right.  Since I didn't want to drill my sump, I use this external pump with tubing.  I have 1" tubing attached to the input of the Iwaki pump which arches up and into the third chamber of the sump.  The output of the Iwaki pump is connected to PVC piping which runs through a high quality ball valve and goes straight to my chiller.  I understand that this is definitely not the preferred way to run this external pump and I was not even sure if it would work when I first set it up.  After installing it though it has worked with no problems at all.  My guess is that the only problem doing it this way is all the power or flow loss due to the bends but that doesn't really matter in this situation as my chiller prefers a lower flow anyway. 
<Mmm, compelled to ask/comment, "I hope the discharge of this line (after going through the chiller) is not "too deep" in the display tank... as the water will back-siphon to this level should the power/pump fail">
The water from the Iwaki pump then goes through my chiller: Pacific Coast 1/10 CL-280 HP.  The water then goes from the chiller and meets up with the water being pumped by the Mag 7 using a "Y tube connector" piece.  Then the tubing with the water pumped by both pumps goes to my return piping in the overflow and back into my display.  To give you a picture, my overflow for my tank is located on the left, sump and reactors in the stand below the tank, and chiller outside of the stand to the right. I have ball valves on each of my return pumps and typically run the system with both open to create the most flow. I also use a ATO of course.  I use the JBJ ATO  The water reservoir is a 5 gallon bucket which is located next to the chiller and a TOM aquatic aqua-lifter pump is used for the ATO.
                Inside the tank I have a Vortech MP-10 powerhead attached on the left upper side in the middle.  To the left and towards the back, I have a Koralia Evolution 750 powerhead near the bottom and a Koralia Evolution 1050 powerhead near the top.  The Koralias are connected to a controller that I have set to run opposite each other every 10 seconds.  I typically set the MP-10 to run on pulse mode with the power turned all the way up.  For lighting I have a Odyssea 48" 716watt Metal Halide System Advance Plus fixture (I know its not the best brand but I am saving for 2 Radions).  The fixture has two 250watt DE HQI metal halide bulbs at 15000K each, 4 54watt T5 high output actinic blue bulbs, and six dual bluemoon LEDs.  There is also two built in fans.  My lights are connected to a timed power strip that runs T5s from 11am-11pm (12 hours), metal halides from 1pm-6pm (6 hours), and moonlights from 11pm-1am (2 hours).  Yes, I really enjoy watching my tank late at night!
                My livestock includes a Lawnmower Blenny, 2 Blue/Green Chromis, Royal Gramma Basslet, Six-Line Wrasse, 2 Percula Clown fish (one orange, one black), and my prized fish: Powder Blue Tang.
<Mmm, needs much (like twice plus) room than this>

 I also have a Black Long Spined Urchin, Pencil Urchin, Blue Linckia Star Fish, and a Brittle Star Fish.  My clean-up crew consists of around 80 Cerith snails, 20 Nassarius Vibex snails, 20 Nerite snails, 30 of several types of hermit crabs, and around 6 emerald crabs.  To cycle my tank back in March, I added the dry sand and rock, added water, mixed the water with salt mix to the right salinity, got it to the correct temp, and turned on the powerheads.
I used the correct portion of Dr. Tim's One & Only Live Nitrifying Bacteria which helped cycle my tank very quickly.  I first added the CUC and then each fish very slowly throughout the next few months.  Lastly, I began to finally purchase coral.  To date I have the following coral in my system: green Acropora frag, Ricordea mushroom, large rock covered with 3 types of Zoanthids, Trumpet Coral, Favites Brain Coral, green tip Torch Coral, 3 small but beautiful Acans from Cherry Corals, 3" neon orange Plate Coral, large Pearl Bubble Coral, and white with purple tip Haitian Anemone.
Before adding any of these corals I treated them with Coral RX following the instructions.  While acclimating all the corals and livestock, I first let them float in the tank to get to my tank's temp, then used my acclimating box which basically uses the drip method.  I allowed everything
to acclimate for at least an hour if not more. All the coral and livestock have done fine and continue to look happy with great polyp extension for corals and a good appetite from both.
                I conduct a 10% water change for my system once a week and do this religiously. Usually before a water change I use a turkey-baster and blow on the rocks, especially in crevices, to get stuck detritus in the water column.  I also siphon the top layer of the substrate if it is dark or covered in algae.  This does result in some debris to float up but I siphon as much of that as I can and really do not believe it is harmful to the system or is harmful gas or anything like that.  I make sure the salinity in my tank is always in the acceptable range (1.024-1.026 using refractometer) and always make sure there is water in the ATO reservoir. 
I have my own RO/DI unit and only use RO water for anything in my system.  I have a TDS meter and the water I use never reaches above 10 ppm (this usually only occurs right before I change the filters, thus the TDS in the water mainly used is 3-4 ppm if not zero).  I have used 2 different brands of salt while maintaining my system.  I started using Reef Crystals Reef Salt.  I then switched to Kent Reef Salt due to the great deal I got for a full bucket.  That ran out last week and now I am back to using Reef Crystals Reef Salt which I have heard great things about.
<The IO brand and Kent's have had occasional troubles... alk./Ca imbalance issues. Search/read on WWM re>
  Having good heaters and a chiller on my system allows temp to not be a problem.  I keep the temp in my tank between 77-78 F, and there is never a swing of more than 2 degrees in a day.  I clean my skimmer cup when it is full, usually once or twice a week.  I also religiously wash my filter socks.  I do this by running them in hot water, flipping them inside-out, and washing them in the washer using no soap.  This gets them nearly as clean as new and only takes 20 minutes.  Other maintenance includes scraping the glass walls which needs to be done about every 2 days. I feed my fish usually only once per day.  I use frozen squares of Mysis shrimp, brine shrimp (the one that says "promotes health!"), and a marine mix.  I put each in its own small container, rinse them, and add tank water to them to thaw in.  I use a syringe to feed them this food.  Usually I go through about 2 squares per week of the marine mix and brine shrimp and 4 squares per week of Mysis shrimp (I also feed this to my corals).  I also feed a little amount of New Life Spectrum Marine Fish Formula Pellets and New Life Formula Two Flake Food every time.  I also feed my Tang about 4 times per week Nori (dried seaweed) which he goes crazy for.
                I test my system's parameters quite often.  I definitely do this once a week, if not more.  For the first 3 months my system was setup I only tested for PH, Ammonia, Nitrite, Nitrate, and Salinity.  When I stared to think my system was ready for corals I also began to test for Magnesium, Calcium, and Alkalinity.  The test kits I use are API for PH, NH4, NO2, and NO3, Salifert also for PH, NH4, NO2, and NO3.  Red Sea for Mg, Calcium, and Alk.  I also use a Hanna Phosphate Checker and Hanna Alkalinity Checker.  Also, like I stated before I use a refractometer to measure salinity and calibrate it often using calibration fluid.  I heard that the accuracy of API test kits are often questionable so I invested in Salifert. When comparing the results I feel that API gives a pretty accurate measurement so I personally look at API results sort of as a "ball park" figure and still use them often.  If anything is in question though I reach for the Salifert tests.  In the beginning, my system's parameters were great and following what is expected in a cycle and the start of a tank's life.  After 2-3 months I began to test for Mg, Calcium, and Alk.
As expected the Mg level and alkalinity levels were low.  My Calcium level was not low being at 450.  I purchased the BRS Kalkwasser kit which I plan to use eventually.  This kit included mixing powders to make solutions of calcium, Mg, and Alk to dose to increase the levels to the desired level.
Once that is accomplished Kalkwasser is to be used to keep those levels stability.  This leads into my first set of questions.
                Now that you have a good idea of my system (again sorry if it was too long of a description, but I don't know what info may be relevant to answer the questions I have and there is just SO much to cover to give one a proper overview of one's system). When testing my parameters recently the magnesium and calcium levels have been super high. Here is a listing of my parameters throughout different dates since I've had my system.  I'm thinking if you had a look at this some sense can be made out of it:
Added First Coral
Red Sea Kit
Calcium = 450
Alkalinity =  8.4 dKH
Magnesium = 1200
Red Sea Kit
Calcium = 335
Alkalinity = 9.1 dKH
Magnesium = 1360
Red Sea Kit
Calcium = 475
Alkalinity = 7 dKH
Magnesium = 1200
Red Sea Kit
Calcium = 470
Alkalinity = 9 dKH
Magnesium = 1360
<These values are not "super high"...>
These parameters were when I started adding coral.  I used the BRalculator on their site and dosed the correct amounts of Mg and Alk solution.  As you can see the Alk and Mg levels swung back and forth and the Calcium level increased a little.  At this point I thought the levels were stable enough and began to add a very small amount of Kalkwasser to my ATO reservoir.  Only after a week of doing this I was told by people on a forum to stop adding Kalkwasser because there was no need to due to my only having a few corals.  So I stopped dosing Kalkwasser.  Another thing to point out is that I had been dosing Purple-Up to my system because I believed this would help develop coraline algae.
<Mmm, can help, but not a good idea to mix w/ other alkalinity and alkaline earth supplements>
  I would dose a cap and a half full everyday and did for roughly 3 weeks.  I was told to stop this too because this only adds calcium to my system and I had nothing to consume that calcium (like corals).  So I stopped dosing that as well.
This all happened about 2 months ago in July.  Around that same time my Reef Crystals Reef salt ran out so I switched to using the Kent Reef Salt I had.  I continued my maintenance and water change schedule with no dosing and continued to get more corals.  Luckily all of my corals have been doing
fine despite my some of my parameters not being where I would have liked.
Here is a estimate of what my parameters have been since stopping dosing and switching to Kent Reef Salt:
*API and Salifert Kits*
PH = 8.0
Ammonia = 0
Nitrite = 0
Nitrate = 10-25
*Red Sea Kit*
Calcium = 500+  ****
Magnesium = 1600+  ****
Alkalinity = 7.5-9
*Hanna Kits
*Phosphate = 0-0.06
Alkalinity = Unavailable (I received a bad batch of Alk reagent so the results made no sense...they have since sent me a new reagent for free)
As you can see my Calcium and Magnesium levels are WAY high and have been for some time.  I'm really not concerned about any of the other parameters.  I thought about it and decided to test the Kent Reef Salt after mixing with RO water (or the water I have been using for water changes).  It turns out that that salt water mix also contained Calcium levels of 500+ and Magnesium levels of 1600+.  I continued to use it up as it was nearly gone and hadn't seen any adverse effects from the levels being so high.  Just the other day I finally got a new bucket of Reef Crystals Reef Salt with the Kent Salt now gone.  During the first water change I tested that mixed water of just the salt and again got the same results!  Calcium of 500 and Mg of 1600!!  Here are my questions:
1) What adverse effects will having a high Calcium level have on my aquarium and corals?
<If not too high for too long, none to speak of>
2) What adverse effects will having a high Magnesium level have on my aquarium and corals?
3) Do you know of any way to lower these parameters to the desired levels (Calcium 380-450, Mg 1200-1400)?  If doing more water changes is the only answer, what should I do considering the tests I just conducted on my new salt?
<Just let time go by... they will drift lower on their own>
4) Based on the information provided, do you know what I did wring to get these parameter's levels so high?
<The mix of supplements, presence of materials (rock, substrate)...>
5) To date, my aquarium is showing only small signs of coraline algae growth.  Do you think if I got Calcium and Magnesium under control, it would be more likely for coraline algae to grow?
<Mmm, possibly... there can/could be other influences of consequence at play here>
6) Have the high levels of Mg and Calcium hindered the growth of coraline algae?
<Could be a bit>
7) What would your advice to me be considering the readings I got when testing Reef Crystals Salt mix?  Should I keep it, go back to the LFS where I got it, maybe contact the company?
<I'd keep it, and notify the LFS and Instant Ocean/IO>
8) Based on all the info I have provided about my setup, maintenance I conduct, etc... Do you have any advice, comments, or suggestions to give me the best chance of success?
<To take your time... along w/ enjoying the process... Keep reading, chatting w/ other reefers... "Nothing good happens in reef systems in a short interval">
9) Knowing that I want a thriving mixed reef tank, heavy with SPS, do you suggest any upgrades, different equipment that I have, or additional equipment?
<A larger system (and sump)... not only for the Acanthurus leucosternon, but overall, a bigger volume will be much easier to keep stable, and give you more room to add livestock, enjoy>
My next set of questions relates to my sump setup and some upgrades I plan on doing to it.  Please refer to the part when I described my sump and return pumps.  Right now I use a Mag 7 to power my skimmer and a Mag 7 and Iwaki 30-RXLRT as return pumps.  I plan on upgrading to a Mag 9.5 to power my skimmer as I have heard this is the most efficient pump for the skimmer.  I also would remove the skimmer from the third chamber and put it to the right side of the sump.  I would raise the skimmer a little more, but still have it drain in the bubble trap (just have to add a little more PVC).  This would free up some much needed space in the third sump chamber and give me easier access to the skimmer.  I also want to upgrade to one return pump - a Mag 18.
<Mmm, can your "reef ready" plumbing accommodate the flow here? I'd take care not to overdrive the overflow... again, and get the larger system, w/ larger, more redundancy in overflow capacity. Read here please:
and here: http://www.wetwebmedia.com/SystemPIX/PlumbingPix/Oneinchart.htm
  Instead of two return pumps I would use the Mag 18 to do the exact same thing.  I would have the Mag 18 in the third chamber, then put a Y-tube connector piece, put high quality ball valves on each tube right after the Y-tube connector piece, have one tube go through the chiller, the other tube go towards the return, and have both tubing meet again,
<Better to have going independently back to the main/display and/or the sump>
connect with a Y-piece, and then go to the return.  This would allow me with complete control of the flow through my system and the refugium.
Since the skimmer pump will only be a Mag 9.5 which sucks water from the 1st chamber to the 3rd, and the Mag 18 being so much more powerful than the Mag 9.5, using the ball valves on the tubing on the Mag 18 I could obviously control the overall flow of the tank, but also control the flow through the refugium (2nd chamber), right?
<You don't want "too much" flow through the 'fuge...>
 Lastly, I wanted to add more miracle mud to the refugium.  I have read great things about miracle mud and the trace elements it contains.  Currently I have a 1.5" bed of miracle mud in my skimmer.  I want to add another 1.5"-2.5", making my refugium a "deep miracle mud bed".  I'd like to try this mainly because I've never seen it done before and don't see any reason why not with all the benefits miracle mud has to offer.  Here are my questions:
10) What do you think of these upgrades?
<Am concerned w/ the flow rate that your overflow can safely accommodate; but do agree re switching to one pump instead of two>
11) do you see any problems with any of these upgrades?
<As above>
12) Based on the info I gave you, with the Mag 9.5 in its location in the sump and powering the skimmer and the Mag 18 with ball valves powering the return, would I be able to control the flow through the refugium?  Do you know what type of control I will have with this setup?
<Gone over on WWM: http://www.wetwebmedia.com/marsetupindex2.htm
the second tray... Refugium... pumps/circulation FAQs>
13) Do you see any negative consequences or have any concerns if I went ahead and did this upgrade?
<Again, the added flow rate concerns me>
14) What do you think of me adding more miracle mud to the fuge?
<S/b fine>
15) Have you heard of a deep miracle mud bed before?, see any negative effects that could come from it?,
<Have seen many times around the world (Leng Sy and I are old friends). No worries>
16) Would you suggest I add more miracle mud?
<If you'd like>
17) Do you have any advice or suggestions to make my refugium more efficient/effective (will add more miracle mud, have rock, Chaeto, 24/7 lighting)?
<See the reference above; read>
WELL, that is all the questions I have had.  I really respect all the advice you give out.  You have helped me in many situations through all the info you have given out by answering others' questions.  I really, really appreciate you taking the time to read this, give out your advice/expertise, and answering my questions.  I will continue to seek your help if anything comes up, and appreciate it so much.  If there is ever anything I can help you with please let me know (although I'm no expert...not yet!).  Thanks again and I really look forward to your response ~ Dustin Getta
<Thank you for sharing so well Dustin. Bob Fenner>

Chaetomorpha dying off in low Magnesium environment - 8/17/12
Many thanks for the maintaining the website and answering to our troubled questions. I just wanted to share the experience with dying off Chaetomorpha in low magnesium. I quickly searched WetWebMedia FAQ pages but did not find a link between low magnesium and dying off Chaetomorpha. I hope this anecdote help fellow reefers.
<Assuredly so>
I went with Instant Ocean salt 3-4 months ago to save on cost and gradually developed inability to raise calcium and alkalinity above 375 ppm and ocellaris clownfish <?> 3.5 meq/L respectively. Chaetomorpha is loosely attached
to a glass wall in the tank with 110w LED light. However, the algae has recently stopped growing, and the most lit parts have lost green color and started to shed off. Magnesium was 1115 ppm (Seachem Magnesium test kit) vs. more than 1300 ppm 7-8 months ago. I started dosing Epsom salt and brought magnesium back to 1300 within two weeks.
Chaetomorpha started growing and returned to dark green 'curly' state in a week. I have never dosed magnesium before.
<The ratio (about 1:3) w/ calcium concentration is absolutely necessary w/ much non-vertebrate life>

Here are a few details about the aquarium setup: a 40gal shallow tank with a few soft corals (mushrooms, Zoanthids), LPS (Candy Cane coral, Frog spawn coral, Acan), two unidentified SPS frags, two Ocellaris Clownfishes, Bubble Tip Anemone,
<Mmm, misplaced w/ the other Cnidarian groups here>

 live rock, skimmer and Vortech. The system is 1.5 year old. I dose alkalinity, calcium supplements (Seachem) and iodine (Kent) and have just started Trace elements (Kent).  I might sometimes overdose either calcium or alkalinity as I move from one salt manufacturer to another one but bring parameters back though weekly Ca and Alk tests. I maintain calcium between 400ppm and 420 ppm and alkalinity between 3.0 meq/L and 3.5 meq/L (Seachem tests). I occasionally test nitrates, phosphates and iodine level but have never seen any spike. Corals and other inhabitants have been growing in the system for more than a year. I could not think of any other reason for dying off Chaetomorpha.
<Need measurable NO3 and HPO4... in this "age" of blind chemical filtrant use, this is often an issue>

 I will probably move back to either Tropic Marine or Reef Crystals once I finish Instant Ocean (+
trace + Epsom salt, etc.)
Best regards,
<And you, Bob Fenner>

Frogspawn Irritated by Magnesium Crystals     7/31/12
Last night I dissolved a dose of Seachem Reef Advantage Magnesium crystals in a cup filled with R/O water and added it to my tank. Apparently several crystals didn't dissolve and when I was adding the solution to my tank, and the crystals fell on the frogspawn.
<Needs to be completely pre-dissolved (like a day in advance) before being applied>
The frogspawn immediately closed and then the tentacles puffed up. I checked it about a half hour later and the tentacles appeared deflated.
<I would to... salts burn, are caustic>
This morning, some of the tentacles appeared to be more inflated, but the frogspawn definitely wasn't extending its tentacles. As the day has gone on, it seems like parts of the frogspawn are turning a brownish color and dissolving.
Can you please offer any advice? I have a Polyfilter i could add. I also have some CoralRx, if you'd recommend dipping the frogspawn.
<I wouldn't dip this coral. Would add a 2-3 times dose of iodide-ate to the system water>
Thank you,
<Welcome. Bob Fenner>

Magnesium Fluctuations 5/21/12
Hello to whomever I have the pleasure of speaking with today.
<James with you today Zack.>
 I will start with some information about my tank. I have a 90 gallon saltwater tank with a wet/dry filter, Reef Octopus 150 skimmer, Coralife PC light fixture 2x 10,000K, 2x actinic, 2x Tunze NanoStream 6025's, 2x smaller power heads, 1x Quiet One 4,000 return pump, a 3"sand bed in most areas, about 70 lbs. LR, 5x Nassarius Snails, 1x Super Tongan Nassarius Snail, 2x Turbo snails, 1x Astrea Snail, 1x Large Cleaner Shrimp, 1 Green Mandarin (eats all foods offered and has substantial Copepod population),
<Lucky you.>
1 Hoeven's Wrasse, 2x Ocellaris clowns, 1x Feather Duster, 1x Caulastrea Furcata (Candy Cane), 1x Tubastrea (SunCoral), 1x Tubiporidae (Pipe Organ), 4x Briarium (GreenStarPolyp), 1x Zoanthid colony, 1x (Literally) Yuma Ricordea mushroom, 1x Actinodiscus Mushroom, a quarter sized Favites Pentagonal (war Coral), 1x Blastomussa Wellsi(Blasto), 1x Echinophyllia aspera (chalice) and finally 3x Acanthastrea or the Acan frags. Most everything is frag size maybe slightly larger.
My parameters are as follows:
Sg-1.025            Nitrate-0
Ph-8.2                Mg- 1169 (a bit low)
Ammonia-0         Alk-9.2
Phoshate-1         Cal- 440
I Can't give you an accurate temp. as I have broken my digital thermometer.
But the heater is set to 78 degree and still works.
I originally began this e-mail because I was having issues with one of my Acan frags, I have talked with members of my local aquarium club and I believe that it was brown jelly disease that was affecting the coral.  It seems to be clearing up after dipping it in Coral RX and a dip in Lugol's Iodine.  After looking into this issue with the Acan I was told more advanced information about magnesium and might have discovered another issue, maybe several.  I recently purchased a Red Sea Reef Foundation Pro test kit and a bottle of Brightwell Aquatics Magnesium.  Hence my parameters above the magnesium issue, I have added enough magnesium to raise my Mg. to 1360ppm and then two days later my Mg. is at 1240ppm, and another two days later its back at 1160ppm!  My turbo's have begun to show signs of becoming lethargic, they are losing suction and falling to the sand.  I have saved them about four
times this week.
<This would not have anything to do with the magnesium levels present in your tank.  Likely lack of food.>
I don't know what is causing my levels to fluctuate.  Please elaborate whatever you can on Mg. I guess I am not getting my exact answer after reading through your website.
<Your Mg levels aren't fluctuating, just decreasing which is normal.  You need to determine a dose rate to keep the level around 1280ppm.>
 My list of corals is rather long but like I said everything is frag sized I cant see them absorbing this much Magnesium.  I apologize for the jumping around that I am about to do I am remembering things that I forgot to say earlier.  I have also recently employed Marinelands Activated Carbon because I thought possible allelopathy with the Acan issue.  I have also had a rather large outbreak in Scypha Cilata (Pineapple Sponges).  I know from earlier research on your site that is caused by nutrient issues.  I purchased this tank 10 months ago while it was still running as a saltwater tank.  It only housed a snowflake eel which was rehomed.   It came with a Aquarium Pharmaceuticals, Inc. Saltwater Master test kit, I see no date on the box, do they expire? The pH, Ammonia, Nitrite, and Nitrate readings came from this test kit.  Which by the way, I have never had abnormal readings from the tests indicating problems.  Amazingly talented beginner or faulty test kit?
<Wouldn't hurt to compare readings with a club members kit known to be recent.>
 I will proudly add that there have not been any casualties thanks to this website and some patience.   Although the one turbo snail is worrying me a little.  Thank you for your time in answering my questions. 
<You're welcome.  I'd ensure the snails are getting supplemental food and see if that improves their health.  Reading this article should help you better understand magnesium.
<James (Salty Dog)>
Re Magnesium Fluctuations 5/21/12      5/23/12

Thank you for your timely response James.
<You're welcome Zack.>
I believe you were correct about my snail issue.  I am trying to understand this Magnesium a bit more.  I have posted on my local aquarium club forum about the amount of Mg. that my system seems to be using, which is about 50ppm per day.
<Mmm, you didn't state this in the first thread.  Yes, that's a little high on a daily basis but in a well stocked SPS/LPS tank, magnesium levels can drop quickly.  If what you're saying is accurate, the calcium levels should be dropping also as corals require magnesium in order to absorb calcium.>
I have seen their fully stocked tanks and they do not use this amount of Mg.  Is this common between recently fragged LPS corals and Magnesium usage?
<Possibly, if noticeable growth is seen during the course of one week.>
On the other hand a tank with "adult" corals would it be common for the magnesium usage to decrease as they are not repairing themselves?
<No, they are always growing in healthy systems and will absorb both calcium and magnesium.>
Also what product would you recommend I dose Mg. with?  I understand that Magnesium Chloride and Magnesium Sulfate may not be the best answers here?
<Actually, most magnesium supplements do contain a blend of magnesium, chloride, and sulphate salts.  I've been using Seachem's Reef Advantage Magnesium with good results.  It's possible you may have a bottle of magnesium that isn't blended properly.  Might want to try the Seachem or Tropic Marin supplements, see if it improves any.>
Thank you again for your time.
<You're welcome.  James (Salty Dog)>
Re Magnesium Fluctuations 5/24/12

Thanks again James.  My final question, can I post our conversation or part of it on Marsh Reef as there is another who has had a similar issue?
<I believe Bob would allow you to post a link to the thread but I'm not sure if he would allow a copy and paste.  Bob?> The second half of the message didn't make it I don't believe otherwise I should post a link. <?>
<<Is certainly okay... Our/WWM/all my content is free of use to non-commercial purposes, agencies. BobF>>
<You're welcome.  James (Salty Dog)>
Re Magnesium Fluctuations 5/24/12

My apologies James I did not realize that the second message that I sent to you was updated on the website.
<No problem, just wanted to be sure what you were getting at.>
Please disregard, only the link will be used if this is a problem I will delete.
<Bob did post his response on the dailies.  I pasted this below for you.
"Re Magnesium Fluctuations 5/24/12
 Thanks again James.  My final question, can I post our conversation or part of it on Marsh Reef as there is another who has had a similar issue?
 <I believe Bob would allow you to post a link to the thread but I'm not sure if he would allow a copy and paste.  Bob?> The second half of the message didn't make it I don't believe otherwise I should post a link. <?>
 <<Is certainly okay... Our/WWM/all my content is free of use to non-commercial purposes, agencies. BobF>>
 <You're welcome.  James (Salty Dog)>
  Zack  Thanks. Zack"

Tiger Cowry, and [Mg]  2/27/12
I am currently fighting off a Bryopsis infestation using elevated magnesium (Tech M).
 My Tiger Cowry, usually very mobile each evening, has not moved in two nights.  He shows little signs of distress other than the lack of relocation, but I am curious if you know of any sensitivity to elevated magnesium. 
<Oh yes... all Mollusks, not just Cypreids. Not just too high or low concentrations, but too far out of ratio w/ [Ca].>
Current level is approximately 1680 ppm.
<Welcome. Bob Fenner>
Re: Tiger Cowry  2/27/12
Thank you.  Very much appreciated.  I'll research proper ratios for future reference,
<Please read here re: http://www.wetwebmedia.com/mgmarart.htm
and the Related FAQs file linked above>
but I believe I'll relo him to my mini-tank for the duration of the treatment.
<Ah yes... I would definitely do so. BobF>

Magnesium and Calcium Levels 6/1/2011
<Hello Aidan>
Firstly have to say brilliant site and service.
<Thank you Aidan.>
My tank specs are as follows, a 125gallon 1 and half year old mixed reef with some soft corals but mostly LPS such as Trumpets, Brain, Trachys etc.
I also have 5 Maxima clams in various sizes from 2" up to 6".
My water tests are Salinity 1.025, Alk 11 dkH , Calcium 380 , Mag 1200 Nitrate and phosphate are undetectable due to Biopellets and Phosban.
I use bailing lite to maintain Alk, calc and mag. With the last two months my readings have being very consistent since I increased my Alk part of supplement to 200ml per day. Previously I had a reading of 6.5 / 7 dKH.
<The later is actually a better range.>
Since then even though my calcium and magnesium readings are steady, they are on the low side.
<Maybe just a tad on the calcium but near ideal. Magnesium and calcium should be maintained on a 3/1 ratio.
My question is should I leave well alone or try to increase these.
<I'd like to see the calcium somewhere between 400-425.>
Is the high Alkalinity suppressing these and would I have to reduce the same to increase calcium and magnesium, I would like your advice to get the best growth and stability in my tank.
<Higher than necessary dKH levels can cause calcium precipitation. Better to have left at 6.5-7 dKH.>
Thanks in advance.
<You're welcome. James (Salty Dog)>

Rising Calcium & Magnesium Levels Without Dosing 1/6/11
Dear Bob Fenner,
Hello and happy new year!
<Hello Ioannis, James with you today.>
I would like to hear your thoughts/opinion on a particular subject.
Here is some information about my system
Total system volume ~ 100 liters (50 netto DT, the rest filtration)
Skimmerless/Naturalistic approach to filtration
25cm RDSB with18kg Ocean Direct Oolite and 9kg Aragalive on top
Refugium with a large growing ball of Chaetomorpha
PH = 7,98 (at 10:00 with refugium lights on and RDP schedule). When the DT lights go on PH climbs up to 8,28)
KH = 7,0 dKH
Ca = 455ppm (double checked with Salifert and Coral Shop tests)
Mg = 1500+ppm (double checked with Salifert and Coral Shop tests)
NO3 = 0ppm (I am actually trying to raise this to about 1-1,5ppm for my LPS corals but the RDSB is very effective and no matter how much I feed the tank it wont go up..)
PO4 = <<0,015ppm
Dosing: NONE
Water Changes: Mainly 15% per week but the last 2 months I only did 2 water changes (didn't have time..)
Salt: DD H2Ocean+
Anyway, my main concern is about the Magnesium level. I am aware it should ideally be roughly 3 times as much as the Calcium level, hence my question.
The last months I have only seen magnesium and Calcium levels rise without dosing anything. Normally you would expect these to decrease as corals use them up (my corals do grow, although not fast).
<Is because they are not absorbing the calcium as fast as they should.>
My tank also contains a healthy amount of coraline and adding the Chaeto to the equation would normally lead to a fair take-up of magnesium.
<Not necessarily.>
The only reason for climbing Ca and Mg levels that I can think off is the massive RDSB. Given it is utilising aragonite sand, it should be (dissolving at a lower PH) giving out more calcium and magnesium than my corals use.
<Cannot dissolve that fast to produce the readings you have. If that were the case, the carbonates produced would give you a higher dKH reading than you presently have.>
What are your thought on the situation and where should I start to be concerned? I am aware that more frequent water changes should decrease the magnesium levels but I am afraid that it might still be rising fast enough that it wont make much of a difference.
Are there any other options? How about slightly raising the KH so that the PH drops less during night? I am hoping that this would lead to less aragonite sand dissolving..
<Whenever someone tells me their Ca and Mg levels are rising without dosing raises a red flag.
Something is amiss here as the corals are not able to absorb the available calcium present. I'm thinking one of the problems may be that your salt mix uses chelated calcium and if so, this makes it more difficult for the corals to absorb especially when higher levels are present such as yours.
Chelated calcium has a tendency to bond making it more difficult to take  out of solution, similar in respect to chelated copper used for parasitic diseases. Presently, I am only aware of one salt mix that does not use chelated calcium, and that product is Tropic Marin, but there may be others that I am not aware of. Since I've been using Tropic Marin, my SPS growth is amazing and I find myself dosing Alca-Balance on a weekly basis to keep the calcium level up. My suggestion to you is to do some aggressive water changes
to lower your Ca and Mg to somewhere near 400ppm Ca and 1200ppm Mg...a three to one balance. If the salt mix you are using does contain chelated calcium, which it likely does, keeping the levels as stated above would make the calcium a little easier to absorb.>
Kind Regards,
<You're welcome. James (Salty Dog)>
Re: Rising Calcium & Magnesium Levels Without Dosing 1/6/11 - 1/7/11
> Whenever someone tells me their Ca and Mg levels are rising without dosing raises a red flag.
> Something is amiss here as the corals are not able to absorb the available
> calcium present. I'm thinking one of the
> problems may be that your salt mix uses chelated calcium and if so, this
> makes it more difficult for the corals to absorb especially when
> higher levels are present such as yours.
> Chelated calcium has a tendency to bond making it more difficult to take
> out of solution, similar in respect to chelated
> copper used for parasitic diseases. Presently, I am only aware of one salt
> mix that does not use chelated calcium, and that product
> is Tropic Marin, but there may be others that I am not aware of. Since
> I've been using Tropic Marin, my SPS growth is amazing and I
> find myself dosing Alca-Balance on a weekly basis to keep the calcium level
> up. My suggestion to you is to do some aggressive water changes
> to lower your Ca and Mg to somewhere near 400ppm Ca and 1200ppm Mg...a
> three to one balance. If the salt mix you are using does
> contain chelated calcium, which it likely does, keeping the levels as
> stated above would make the calcium a little easier to absorb.
Hi James,
<Hello Ioannis>
Thank you for your fast response.
<You're welcome, but please do not alter the original thread, reply only.
The info you deleted is useful for my review/response. I can't possibly remember what each individual
querior has stated in their query.>
I have been using DD Ocean H2O+ Salt since the beginning. What you are saying about chelated calcium makes me wonder. A few months ago I had to dose calcium and magnesium and was even planning to build a calcium reactor to keep up with usage. This was before I upgraded my filtration with an RDSB
(some months before actually). Do you have any thoughts for what could have caused this drastic change?
<The same as what I stated in the first thread....the possible build up of chelated calcium making it more difficult for the animals to absorb.
Your upgraded RDSB filtration and rising calcium is purely coincidental.
As I mentioned in the first thread, if your oolitic sand/aragonite were dissolving that fast, your dKH would be higher than the 7 dKH you mentioned.
The end product is carbonates and carbonates will raise dKH levels.>
By the way, which Tropic Marin salt are you using?
<I use their standard product, nothing special.>
I have a bucket of Tropic Marin Bio Aktif salt in my basement but this one has to be used in combination with a skimmer which I am not really planning to use a skimmer any time soon.
Would it be wise to switch salts every now and then for this matter (lets say one time TM and the next time DD?
<I would not alternate, choose one and stick with it. I've used Reef Crystals for years and years, but since switching to Tropic Marin I have noticed considerable improvement/growth in my stony corals. It's quite obvious to me both visually and in calcium test results, that they are absorbing a considerable amount of calcium.>
<Ditto. James (Salty Dog)>

Re High pH And Tons Of Hair Algae/Lacking Useful Info/Now Toxins/Now Anemone Health/Now BGA 4/18/10 - 8/10/10
Hi James,
So I finally got my Salifert Magnesium test kit and a can of Alca Balance delivered yesterday.
The Magnesium tested at 950. I believe that is quite low and explains why dosing with Kalkwasser has little effect.
<Really has more to do with the ability of corals to absorb calcium.>
My question is, why would the tank be so low given the amount of water changes I've been doing lately
(10-20 gallons a week on my 90 gallon tank with a 20 refugium)?
<The animals do absorb magnesium, are like other elements, need to be maintained/replaced.>
I know that Tropic Marin has Mg and it's not like my tank is full of corals right now.
<For your own peace of mind, measure the magnesium in a newly mixed batch of saltwater.
You may or may not be surprised. Tropic Marin Pro Reef Salt does contain more magnesium (900-1250ppm)
than the less expensive version of their mix which I believe is what you are using.>
I had a tiny container of Red Sea Magnesium additive that I put in the tank but at the levels I see, I'm sure I will need more supplements to continue raising till I get over 1200. From what I've seen, getting some Epsom Salt
from the pharmacy would to be the easiest rout for me (feel free to suggest a different route).
<I'd shy away from using Epsom Salt as most good brands of magnesium supplements
contain a combination of magnesium and minerals to help promote essential biochemical processes in the aquarium.>
I dont want to get things totally out of balance by dosing Kalkwasser, magnesium, and/or Alca Balance, etc. Could you point me in the right direction as to how to bring things back to par?
<Magnesium is a major element of saltwater and should have nothing to do with promoting imbalances in your system. It is best to improve one parameter at a time and I would start with magnesium, followed by dosing Alka-Balance which should bring the calcium level up and maintain dKH. More information can be found on these subjects by searching our site.>
As always, thanks for your input!!
<You're welcome. James (Salty Dog)>

High Ca And Mg - How To Get Them Down! 6/29/10
Dear All,
Firstly, many apologies as I'm certain this must be covered in the FAQs somewhere but I can't locate it! I'm currently in the process of setting my system up as a low nutrient tank, using rock and media form a rather neglected system. As such I've been testing the water religiously and doing frequent water changes to get nitrate and phosphate levels down and have noticed that my calcium and magnesium levels are always high (have given
the actual values below, tested using Salifert Profi kits except for phosphate which is tested using the Deltec high sensitivity kit):
Temperature: 25C
SG: 1.025
pH: 8.2
Nitrate: 0.2ppm
Phosphate: undetectable
Ca: 620 ppm
Mg: 1800 ppm
dKH: 9
These values have remained constant for several weeks so am wondering how I can get them to within NSW levels and if it is even desirable to do this?
<Is desirable to keep near NSW levels, high levels of these elements can be detrimental to your system.>
Currently the tank has soft corals, Zoanthids and some LPS (a Duncan and torch coral), so could these levels be due to a lack of corals that require these minerals for skeleton growth (i.e. sps), or could it be due to the salt mix I'm using Tropic Marin Pro-Reef sea salt)?
<Is not the salt, and likely due to unnecessary dosing of Ca and Mg.>
I'm planning on starting with SPS corals in the near future (hence the drive to get the tank in the best condition possible) so want to make sure everything is as close to perfect as possible and that parameters are stable.
<The best way to gradually lower your Ca and Mg levels is by doing 30% weekly water changes which will lower the levels by dilution. It is best to test the water weekly so a dosing plan (if needed) to maintain proper levels can be developed. I use the same salt as you, and I rarely dose Ca and/or Mg.
Many thanks,
<You're welcome. James (Salty Dog)>

Summat about Mg conc., subjective evaluations, who knows what?  4/20/10
Just a little about my tank. Established for 3 months, reef tank, 75 Gal.
Just some soft coral. Drilled tank with a sump and protein skimmer. I have a Reef Lobster,
hermits, various snails, emerald crab and horseshoe crab.
<What/which species? Most are coldwater... incompatible in a tropical setting: Read here: http://wetwebmedia.com/hshoeccomp.htm>
PH 8.3, Nitrates 10-20, Nitrite 0, Ammonia 0,Salinty at 1.025, Phosphate 0.
Magnesium was low.
<How low? Relative to Ca conc.?>
I made a huge mistake as my Mag was low and I was given some bad advice and accidentally overdosed my tank with Dow Mag. Flakes and my Magnesium raised rapidly from 800 - 1100 within 2 hrs. My Firefish died and my
Foxface Rabbitfish is in severe stress. He hasn't eaten in 2 days and is staying hidden and not swimming around. I did my usual water change the day I added the Mag. I have a 75 gal. tank changed out 15 gal. when I noticed the stress my fish were in I immed. did another 10 gal. water change. The only thing I can guess is the rapid increase in Mag. affected my fish. I noticed today that my Foxface appears to have Pop-eye. Would the Magnesium have caused this?
<Mmm, could>
I don't know what to do.
<Change out a good part of the water. Stat!>
Water appears to be fine and my Foxface looks terrible. I did have Ick in my tank from a new Blue Hippo Tang addition and it did affect all my fish, but the Hippo has been put in a QT tank and is being treated with copper at
the LFS. Any help would be appreciated. Thank you, Ginny
<... Need real numbers for what you give opinions re... Something else beside simply raising [Mg] is at play here... but can't discern from the data presented. Bob Fenner> 

Mg question, proportionality with Ca, importance   9/2/09
I contacted Lou @ Tropic Marin a while back as to low magnesium levels affecting calcium readings and received his reply.
I've never found any info as to such, as I was interested in knowing, so I thought I'd contact Lou for his input.
<I do agree with the stmt.s presented. BobF.>
Subject: Mg question
Hi James,
This is Lou Ekus contacting you from Leslie's computer as mine is in the shop. Sorry for the delay in getting back to you on this. Not having my computer has thrown off my whole schedule and work systems. I contacted our lab in Germany and the answer to your question is this. Low Mg concentrations will NOT affect the Ca reading on test kits. You are correct that it does affect the Ca absorption. And you are also correct that if you look at Ca supplements for human use, you will notice that same 1-3 ratio that is talked about so much. Not just interesting'¦'¦but based in good solid chemistry.
Once again, Sorry for the delay in getting back to you. My computer is supposed to be back tomorrow'¦. yeh!!!
All the best,
From the computer of:
Leslie Ekus
Tropic Marin USA
44 Center Street
Montague, MA 01351

Knop C Calcium Reactor, Mg source  -- 08/23/09
Hello there.
I was wondering if there is anything I can add to my reactor aside from the arm media to supplement the magnesium in my system? Seems I read somewhere that I can add something along with the standard reactor media that will dissolve and replenish the magnesium in my tank.
<Mmm, yes... Many folks use a "clean" source of Epsom Salt, Magnesium Sulfate... and there are other Mg compounds that can be of service>
One more question I have is about Halimeda. I have this stuff growing like crazy when I run my Calcium reactor. I know that it is a calcareous algae but is there something else to check for to keep this stuff under control?
<Yes... see WWM re>
I was under the impression that this stuff does not use phosphates or nitrates for food.....which are zero in my testing for them.
Thanks again for all your time with everyone's questions. I have been reading your site for years and refer many there for your excellent advice
for us in the hobby.
Jay S
Vancouver Wa
<Welcome. Bob Fenner>

Calcium problems  6/20/09
Hi Crew,
I have long term problems keeping my calcium up. I use Instant Ocean Reef Crystals,
<Mmm, this product is proving inconsistent in composition... For one thing, I would look into another brand to test>
changing about 6-7 gallons per week in a 75 gallon tank. I also dose with B-Ionic most days, using 60 ml per day, which is about 3 times the recommended starting dose.
<... of both parts?>
I also add about 1 tsp. Reef Buffer most days,
which I dissolve in freshwater that I add for topping up.
<... I would just stick with one brand/manufacturer>
In March and April, I had alkalinity of 3.0 mEq, and calcium of 375 ppm.
Not great, but not alarming, and reasonably balanced, as I understand things. I did not check again until this month (June) when the readings were 3.0-3.5 mEq and 280 ppm. So my calcium had really fallen off.
<As well as alkalinity... summat is off here>
I have pretty satisfactory coralline algae growth, though it looks faded when my calcium gets low, as it is now.
<Mmm... is the coralline "sucking up" available biomineral AND alkalinity...? What about your Magnesium? Is this in about proportion? Have you checked Mg?>
I also have an attractive growth of some kind of Halimeda algae, which I am particularly fond of because it presumably competes with the Grape Caulerpa that I wish I had never introduced into the tank.
First question: is it this Halimeda that depletes my calcium? Should I remove it or cut it back?
<All the stated macroalgae could be implicated>
When I found my calcium low, I tried a strategy I had tried once before.
Knowing that you guys frown on using the standard calcium supplement (calcium chloride),
<I would not do this>
I decided to add close to the maximum dose of Reef Calcium (calcium gluconate). So I started 50 ml per day. After a few days, I noticed some of my soft corals not opening up. After a few more days, I started to get cloudy water and my skimmer production went way up. You'd think I had some die-off in the tank, but there is no die-off that I can identify.
<Likely just chemical cloudiness>
The fish and inverts (2 Cinnamon Clowns, Royal Gramma, Yellow Clown Goby, 2 Peppermint Shrimp, one Atlantic Hairy Triton snail) seem fine.
As I mentioned, this is the second time I have attempted heavy dosing of Reef Calcium, and in fact I had a similar experience the first time I tried it. That time, however, I had had a concurrent circulation pump failure that may have gone on for a couple days before I noticed it (the other circulation pump, plus 2 skimmers, plus 2 power filters were all still running). In any case, I decided that the pump failure was the cause of that episode of cloudy water and heavy skimmer production. But now I'm wondering if it was the heavy dosing with Reef Calcium.
<Likely so>
Second question: do you think the Reef Calcium is causing my cloudy water/heavy skimmer production?
I just looked again at information about calcium supplementation on your site, and found at least one exchange that suggested maybe calcium chloride is not all that bad.
<Some folks use... "all the time"... but this molecule has some inherent drawbacks/downsides... that one must understand, anticipate... Not a good material for most westerners...>
So third question: if I am changing close to 10 percent of my tank water weekly, would it be OK for me to use calcium chloride a few times a year to help maintain calcium? Is the concern about chloride ion build-up overblown?
<Again... I would not use this material... there are other, far better, safer methods of achieving high, consistent biomineral levels>
I know that Kalkwasser or a calcium reactor is your preferred solution, but so far I have not been willing to invest my time and/or money in those solutions.
Thanks for your thoughts.
<Please do read re Mg, and measure for this... I suspect this may well be your trouble here... Bob Fenner>

Re: Calcium problems, actually Mg     6/24/09
Hi Bob,
Thanks for your previous reply.
I obtained a magnesium test kit (Seachem) and just ran the test. My result was 1250-1375 ppm, which is just about what natural seawater is supposed to be. If my calcium is 275 (per the last test a few days ago), my magnesium is around 4.5-5.0 times my calcium. Is this a problem?
<Mmm, yes, or at least potentially... You want this alkaline earth element to be about 3 times the concentration of Ca... much more or less can be problematical>
A couple of other things have occurred to me since our previous exchange.
The reason I had that circulation pump failure was that the impeller stopped spinning on its shaft due to white-ish deposits.
<Ahh! A good clue>
Within the last two weeks, I systematically soaked all my impellers and shafts in white vinegar to remove similar deposits from all of them. Is it odd that I would get some kind of mineral deposition at the same time as I struggle to maintain calcium and alkalinity levels?
<Not odd at all... coincidental>
For what it is worth, I have been making my salt water using municipal tap water run through a Pur tap water filter, and immediately
<I'd aerate this just made water for an hour or more>
adding the salt mix to that water. I then let this age for at least a week, often much more as I use two 30 gallon Roughneck trash cans for this, and it usually takes 3 weeks to get through one while the other is aging. I put my used (brown, but not black) Polyfilters in these cans, putting some of this filter material (cut into smaller pieces) into Hagen Quick Filters fitted to Hagen power heads, in the hope that this might remove any additional impurities from the municipal water.
<Interesting... good technique>
Often, it seems to me that it takes more salt mix to hit a specific gravity of 1.025 than it used to take with the RO/DI water I used in my previous home. I had just assumed that I was failing to correctly count all the gallons of water I was adding to the trash can, and so I always seemed to need more salt than I expected to. But could there be something else going on here?
<Mmm, yes... likely on the salt manufacturer's end... using hydrated salts... It often occurs that using a "stock 50 gallon mix" with a total of 50 gallons volume does NOT result in a specific gravity of normal seawater...>
Any further thoughts you might have would be welcome.
<Am in a bit of (personal) turmoil here presently... Will cogitate (hopefully furiously), and chat with you further on. BobF>

High Magnesium and corals losing color 3/15/09
Hi, I have a 175 gal reef. Calcium is 450 mg/l alkalinity is 9 dKH, Magnesium is 1800 ppm.
<Mmm, I would remove a good deal of the water in this system, and re-fill with new seawater with less Mg>
Everything was fine until a friend of mine gave me this magnesium supplement he sells, but he gave it for free since the instructions were wrong, I couldn´t find the right instructions in his homepage either, so I added 2 full caps and the day after I noticed that my Montiporas were losing color. Only the Montis: rainbow, superman, orange capricornis and green capricornis, the Monti palawensis was not affected and neither was the sunset Monti. Acros and all other corals were not affected.
<... not yet>
The Montis affected look rather pale, the Magnesium level was probably around 1600 ppm and this supplement raised it to 1800 ppm. Is this the reason for the pale colors?
<Could well be... directly or not>
Some people suggest that is good to have high magnesium as it will improve coralline etc.
<Mmm, not to my knowledge... about three times Ca conc. is ideal... more gets worse>
My Mag levels have always been high, the average was 1300 ppm until I started dosing Mag supplements then it went up. A curious thing is that my green Monti cap has never had a good coloration, it has always looked pale, I´m wondering if high mag has this effect on corals?
<Can, yes>
Now the question is how to lower the Mag, I heard this is done with water changes, I did a water change last week before adding the Mag supplement which raised Mag, so I´m wondering if I can just wait 4 more weeks to do the water change as usual or I should treat this as an emergency and do the water change now to lower magnesium?, is there an urgency?.
<There is... again... diluting with new water of lower [Mg] is called for... stat>
Also for my calcium I use Seachem's advantage calcium which "maintains magnesium" does that mean it will keep Mag at 1800 ppm as long as I keep using it?.
<Depends on how much you use... I would use three times Ca levels as a target, and NOT add the Advantage if Mg is about three times this concentration>
Also what is going to happen with the corals that went pale in coloration, will they die from this?
<Hopefully not>
, or they will just go back to normal in time?.
<Hopefully so>
Did they become pale because of High Mag levels or because the increase on Mag levels was to much to fast?
<Can't say... but is a possibility that it is the sudden and/or finished high degree. Bob Fenner>

Mixing Salt/High Ca And Mg Readings 12/4/08 Hi guys, <Hi Jamie> The wealth of this site is astounding! You must be really pleased at offering this kind of quality advice to all. Nice one! <Thank you.> I been having some issues with Tropic Marin Pro Reef salt. After mixing with RO Water, I have tested the water and found very high levels of Calcium (550) and Magnesium (2000). I have been seeing this high level in my Marine Reef system since the beginning, but could not understand why. After testing the RO water before mixing (zero levels), I decided to test the salt mix, which is when I found this seemingly unusual level. This is the second batch of salt I have had this issue with. As a result of these excessive levels, some of the corals/polyps/xenia have started to shrivel, and I have never had any algae growth despite increased lighting etc. I have purchased 2 different brands of test kit to make sure I have not had a bad test batch, but the reading are the same. Have you experience, or even heard of this before? <I have not, Bob may have. I do know that they provide a reliable supply of both calcium and magnesium in this product, but I wouldn't think that much.> I mix the salt over 24hrs to 26 degrees C with a small pump and air stone to around 1.026. I am at a loss of what to do next, except complain to TMC. Thoughts <I've contacted Tropic Marin for their input on this and as soon as I hear back from them, I will respond to this.> <<Ah, good James... Hopefully they will have a substantive reply. Good artificial saltmixes do contain unnaturally high levels/concentrations of both biominerals and alkalinity... by design... to "resist" their deficiency in captive settings. RMF>> Many Thanks, <You're welcome. James (Salty Dog)> Jamie Stokes

Re: Tropic Marin Pro Reef Salt -- Extremely high reading of Calcium and Magnesium during mixing. Any ideas? Hi guys, <Hi Jamie> The wealth of this site is astounding! You must e really pleased at offering this kind of quality advice to all. Nice one! I been having some issues with Tropic Marin Pro Reef salt. After mixing with RO Water I have tested the water and found very high levels of Calcium (550) and Magnesium (2000). I have been seeing this high level in my Marine Reef system since the beginning, but could not understand why. After testing the RO water before mixing (zero levels), I decided to test the salt mix, which is when I found this seemingly unusual level. This is the second batch of salt I have had this issue with. As a result of these excessive levels, some of the corals/polyps/xenia have started to shrivel, and I have never had any algae growth despite increased lighting etc. . I have purchased 2 different brands of test kit to make sure I have not had a bad test batch, but the reading are the same. Have you experience, or even heard of this before? I mix the salt over 24hrs to 26 degrees C with a small pump and air stone to around 1.026. I am at a loss of what to do next, except complain to TMC. Thoughts? <Jamie, I've pasted the email I received from Lou Ekus, Tropic Marin, regarding your concern with Tropic Marin Salt. He asked that you call him if you like. You will find his contact information at the end of the message content. James (Salty Dog)> Many Thanks, <You're welcome.> Jamie Stokes Hi James, Unless there is something going on that is completely out of the range of anything Tropic Marin has ever seen, I can have no explanation for numbers like these. In fact, in RO/DI water, it would be impossible to get our Ca and Mg that high without seeing lots of precipitation. Let this person know that and ask them to contact me directly and I'll help them figure out what is going on. I have serious doubts about these readings even though he states that different test kits were being used. Also, please let him know that he needs to contact Tropic Marin NOT TMC. Thanks All the best, Lou Ekus Director of US Operations Tropic Marin USA

Supplement Juggling Act...Igor Lives... Ca, Mg and dKH 12/3/08 Hi there, <Hello Richard> First, the problem (or at least what lead me to conduct some tests). My Acros and Montiporas look bleached or all brown (as opposed to individual colours) but polyp extension is good. Corals showed some growth in first 2 months in my tank, but over last 2 months there has been almost none. Parameters, SG 1.024, temperature is 24-26C, ammonia=0, nitrite=0, nitrate=0, phosphate=0. I know you will say these are probably being consumed at source so not strictly zero but I have focused on nitrogen cycle items being the cause of discolouration to the detriment of other tests and herein I think may lie the problem? <Mmm, I wouldn't look here.> Upon deciding to test more widely, I have found that magnesium was approx 800 ppm/l, calcium was 320 ppm/l and alkalinity/carbonate hardness was around 20dKH. <With magnesium at 800ppm, your corals are only able to absorb 62% of the calcium available which in turn means at a calcium level of 320ppm, only 198ppm is available to the corals. Magnesium must be kept close to 1280ppm for the measured calcium to be 100% available for the corals. The high dKH is also hurting you in this regard and a dKH of 8 would be a good target goal. The Europeans are now striving to keep dKH levels as low as 7dkH giving better dKH, calcium, and magnesium balance. (re phone conversation with Lou Ekus of Tropic Marin)> As mentioned above, these readings have lead me to move away from suspecting nitrates/phosphates as a problem and to now suspect the problem is with these readings. <Absolutely!> Since these readings, I have added magnesium and have managed to get this level up to around 1150 ppm. It seems difficult to go beyond this and I don't want to start dumping too many supplements in the tank. <Getting the dKH back to normal would be my first concern.>  I am now trying to figure out how to raise the calcium and lower the dKH level and would appreciate your comments regarding:- <Here is a good place to start. http://www.wetwebmedia.com/calcalkmar.htm> 1) addition of small amounts of seltzer. Is this method a mad scientist approach or is it OK? <Mad scientist> I tried it and the dKH went down to around 8dKH after adding a few fluid ounces, which really surprised me. I can only assume the test kit is working but I worry about such a large swing in what was a very short time. <Quite possible the seltzer could have had an effect on your reading. Did you check it again the following day?> 2) Whilst the dKH was down to 8ppm, I started adding small amounts of Kalkwasser and bio calcium. Although the calcium level rose to maybe 340 ppm, the dKH level has also risen to around 18dKH again. <In your particular case, I wouldn't be using Kalkwasser because of what it can do to elevate dKH levels.> 3) How much Kalk should be added and how? I don't have a Kalk reactor and I used to mix with some vinegar and add around 1/2 teaspoon dissolved in vinegar and then diluted in 5 litres of water. <No more vinegar, unless you understand what your doing and why, stop adding supplements such as this and seltzer. You are likely to create more problems.> I would then add this manually during the evening in small amounts. I am starting to wonder if this was excessive and that my corals (all small frags) never took up this Kalkwasser and that I slowly but surely ended up raising carbonate levels by blindly and continuously adding Kalkwasser? <As I stated above, the corals cannot absorb all the calcium available unless magnesium is at the proper level.> I am now loathe to keep trying to balance this out with supplements/more Kalk as it seems like things will just escalate into a supplement 'arms race.' Should I try partial water changes? Tank is around 260 lites and I was thinking of 15-20 litre water changes every day for maybe a week or so. <I would go this route, no more supplements and change 10% of the water every other day. Monitor calcium, magnesium, pH, and dKH daily and keep a record of such. Use a salt rich in calcium and magnesium such as Reef Crystals or Tropic Marin. I've been using Tropic Marin and am very pleased with the product. My second choice would be Reef Crystals. Read the link and related articles/FAQ's I've pasted above. Do get back with me in a week or so replying to this entire email along with your test results. James (Salty Dog)> Richard

Importance of Magnesium  11/25/08 Hi Bob, <James> I had a very nice phone chat with Lou Ekus yesterday. Lou is the head cheese for Tropic Marin, USA in regard to product support. I had sent him an email with a question I had about calcium. He emailed back and asked for my number so he could call and chat in person. A very nice business gesture indeed. The conversation led to the importance of magnesium in reef tanks containing stony corals and/or clams. He stated that the calcium loving animals can only absorb the all the calcium available when the calcium and magnesium are kept at a 1 to 3 ratio. <This is my understanding as well> Typically on the reefs, calcium ranges from 400-420ppm with magnesium being at 1200-1220, again a 1 to 3 ratio. If a tank is kept at 400ppm of calcium and only 800ppm of magnesium is present, only 60% of the calcium will be available to the animals. <Mmm, and other ultrastructural, physiological problems>  He stated that there is no reef salt made that can maintain these levels, even with a weekly 10% water change! Many aquarists believe that by using these reef salts they no longer need to supplement because their calcium always reads 400ppm and up. This is indeed a bad sign since the calcium is not being absorbed by the animals in the amount needed for proper growth, which in turn means that magnesium levels can be drastically low. A healthy stony coral can absorb 30-50mg of calcium per day, clams even more. On another note, people suffering with osteoporosis are given medication that contains calcium, and ironically magnesium is added to the medication at a 1 to 3 ratio. Feel free to post this in the dailies if you'd like. <I will> Lou had told me to consider him as a source to any questions I might have in this area or other supplements. Lou graciously provided me with his phone number and an invitation to contact him any time. Sure sounds like Tropic Marin is another company with great product support. Regards, James <A winning brand for sure. Thank you for sharing. BobF>

Magnesium Fluctuations 10/31/08 Hi crew, <Hello Tim.> I've been a little troubled by fluctuating magnesium levels. I have been testing frequently over the last few weeks to get a better understanding of my tanks average weekly/monthly demand. The results have me confused. My magnesium appears to be fluctuating from 1350 to 1200 within a few days. This is the third week that I have experienced these test results. My most resent test results from earlier today have me so confused I've decided I should get an experienced opinion.  I am using a newly purchased Salifert test kit. My results from today are as follows: Tank water before water change ? Mg 1320 Water change mixture: Mg 1350 (used Kent Tech-M to achieve this level) Tank water after water change ? Mg 1200 (water tested around an hour after water change) *each level was tested multiple times for accuracy. In you opinion what could be causing this? <One explanation is the Kalk, some kalks can precipitate the Mg, lowering your level. If it is near where the water is collected for the test it can explain the drop. Your Ca and Alk levels, while what are considered good by most reefers, are on the high end. Calfo's marble analogy applies here, the water can only hold so much: http://www.wetwebmedia.com/calcalkmar.htm> Additional measurements of tank water before water change: pH 8.3, Sg 1.025, Temp 80, Ca 420, KH 13.5, Sr 1-4 (all tests w/Salifert) Additional measurements of water change mixture: pH 8.3, Sg 1.025, Temp 80, Ca 430 (used B-Ionic, Kent Calcium), KH 9.3 (used B-Ionic), Sr 16 (used Kent Strontium) Additional measurements of tank water after water change: pH 8.3, Sg 1.025, Temp 80, Ca 420, KH 12, Sr 1-4 (can?t seem to get Strontium to proper levels)*just realized my water change mixture testes around 4 Sr, so this was the first week I boosted with Kent, I?m also adding it to my Kalkwasser drip to hopefully bring the level up between 10-16. In addition to the water change, a new PolyPad (changed weekly), Kent Carbon (changed weekly), Phosban (changed quarterly) were added (all three are run constantly). As mentioned above I dose Kalkwasser nightly, as well as 24/7 protein skimming, and weekly 20% water changes. I have literally 10-20 hours of testing time invested in the last month and I just want to get this right so I can relax and get on a monthly/as needed testing regimen. <I hear you! A Mg level of 1200 is fine, nothing to worry about.> Your help is GREATLY appreciated, Tim Robitaille <Very welcome, Scott V.>

Magnesium Chloride Hexahydrate…A Search For Cheaper Supplements - 10/24/08 Dear Crew, <<Cheers Simon>> I am hoping that someone may be able to help with my problem. <<I shall try>> I have a 200+ gallon Marine system and have managed to locate calcium-chloride, sodium-bicarbonate and soda ash from a swimming pool company that I use to maintain my calcium and alkalinity. Obviously, I have done this to save money because I would rather purchase exactly what my aquarium needs rather than spend a fortune on magical potions! <<Quite understandable…and though I also do some of the same, this approach is not without risks re unknown impurities in such compounds>> Also the bottles of magnesium in particular are expensive considering that even adding the whole bottle hardly raises the levels at all! <Hmm…do try Seachem's quality product line>> For my magnesium I have managed to locate Epsom salts, but from what I understand these are Mg sulphate, so if I use these too often I will have a build up of sulphate in my tank over time. Does anyone have experience with this being a problem? <<I utilize a Kalkwasser reactor and have used Epsom salt to replenish/replace magnesium for years…I am unaware of any problems directly attributable to a buildup of Sulphate>> If so, then is the problem easily rectified by water changes, or are these changes going to have to be massive ones to keep the sulphates down? <<Routine (whatever that is [grin]) water changes will be fine>> I have read that magnesium-chloride-hexahydrate is better to use, but I cannot find any of this stuff for sale in the UK on the web. All I have managed to find is magnesium chloride. Is this the same stuff? <<It is…the "Hexahydrate" refers to the water content/ratio of the crystals. And actually…utilizing a combination of Magnesium Sulphate AND Magnesium Chloride would be best (these are the constituents of Seachem's excellent product)>> I have found a company that lists the content of their product and it seems to contain various trace elements such as lead which does not sound great to me. Their product can be found here: http://www.rsminerals.co.uk/40.html - does this look to you like something that I could use or not? <<Can't say for sure…the product states that it is used in animal feeds so one would assume the product to be safe "enough"…though 0.5ppm Lead does seem like a lot to me>> The guide that I have been using is here by the way: http://reefkeeping.com/issues/2006-02/rhf/index.php. I was wondering if any of the crew (maybe Eric Russell?) with larger tanks might tell me how they maintain their magnesium levels. <<As stated, mate…simple Epsom Salt for the most part…though I do occasionally purchase Seachem's 'Reef Advantage Magnesium' for the Chloride content…and more recently have found a (safe?) source of both Magnesium Sulphate and Magnesium Chloride salts at a very economical price (http://www.tbaquatics.com/shop/index.php?main_page=index&cPath=8&zenid=a8b07b07d15f49e4b946d8922a5361e2) >> Yours in admiration, Simon Trippick <<Happy to share. Eric Russell>>

Re: Magnesium Chloride Hexahydrate...A Search For Cheaper Supplements -10/25/08 Thank you Eric you've been a great help. Simon Trippick <<Ahh! So good to know, and you're quite welcome. Eric Russell>> 

Giant clam malady? Mg toxicity - 09/04/08 Hi Bob (and crew), <Hi Chris, Mich here.> Thanks for the many hours that you have collectively invested in the hobby and in this website. It is a great resource. <Thank you for your kind words here.> I am having a problem with the mollusks in my tank that I haven?t been able to resolve after looking at the snail disease faq, the giant clam disease faq. or Fatherree?s clam book. <OK, hopefully I can help.> My tank? is a sps dominated mixed reef. Salinity is 1.024, pH is 7.8-8.1 (lower than I would like it to be) <Yes.> temp 78.5, ammonia, nitrate and nitrite are all not detectable, PO4 is around .25-.5 ppm (more than I would like), because of my high coral load and the presence of a large clam I am having trouble keeping my calcium and Alk where I would like them to be. My dKH hovers around six and my calcium is around 325. I know that these levels are too low and I am currently investing in a calcium reactor and Kalk reactor, which will be employed under the vigilance of an aqua controller to address this problem. My Mg is around 1300ish. <I think this maybe part of your problem.> I currently dose what seem to be excessive amounts of DT?s 3-part calcium mg and Alk buffer to compensate for bio depletion and to raise pH. <OK.> Lighting is a 10,000K 250W metal halide. Tank turnover is about 50X. I have a 1 inch sand bed which I gravel vac as part of my weekly maintenance. I typically do at least 10% water change every week. (more often 25%). <Husbandry seems good.> I have great coral and clam growth and no algae problems. <Wonderful!> As for fish I?m a fan of a relatively conservative fish load. I have a small flasher wrasse, a Banggai cardinal, a mandarin and a yellow assessor. (no coral eaters or clam nippers) <Great!> On to the problem: About a week and a half ago, my T. crocea (~5.5 inches) decided he was no longer happy as a clam. During the daytime, he remains mostly closed with his mantle mostly retracted. It does open ~75% in the mornings when natural sunlight hits his corner of the tank. It also seems to be expanded to a greater degree when the lights are off (~25%). The clam is still light responsive and appears to have no signs of pinched mantle, white spot, obvious necrosis or parasitic snails. It is located on a small rock on the bottom of my tank about 13? under water (mantle is at a 10? depth). It?s byssal attachment is still quite strong. <OK.> I?m concerned that he hasn?t been opening. <Rightly so.> Since the situation arose, I have employed activated carbon in the tank in hopes of removing any DOC toxins that might be present and have done three 25% water changes in the past week and a half. <Well your carbon usage has likely cleared your water significantly, which may make your clam more sensitive to light.> I would be content to call this an issue related to the clams exposure to light in the tank BUT, I have noticed my Astrea snails have been remarkably lethargic lastly as well. <I think this is likely related to your high Magnesium levels and low Calcium levels.> One snail laid on his side half open for ~12 hours others have not moved for several days on end. I have not noticed any snail deaths. <Here is my theory: You are likely seeing paralysis from the high Mag levels/ low Calcium. Magnesium Sulfate (MgSO4) in the human acts as a central nervous system depressant. It blocks neuromuscular transmission by decreasing the amount of Acetylcholine released by motor nerve impulses. A secondary effect is the relaxation of smooth muscle tissue. MgSO4 is also the most commonly used tocolytic agent, it decreases the frequency and intensity of uterine contractions associated with preterm labor. It is also used to prevent seizures and convulsions..Mag toxicity is a huge concern in something the size of a human, let alone a tiny snails. When MgSO4 is given in a hospital setting the antagonist, calcium, typically calcium gluconate, is kept at the bedside. Patella Tendon reflexes are continuously monitored for signs of diminished or absent reflexes related to the risk of overdose. This is why I suspect your problems may be related to the Calcium level and Magnesium levels in your tank.> Any thoughts?? (sorry for the long email) <I do think this is a water chemistry issue. I think you should try raising your dKH, pH, and Calcium levels and lower your Magnesium levels.> Thanks, <Welcome,> Chris <Michelle Lemech MS RN>

Re: Giant clam malady? 10/8/08 Hello Mich, <Hi Chris,> Thank you for you well thought out response! <Welcome!> I think you are on to something. <Well, makes sense in theory I think.> In retrospect, I *think* I noticed more mantle extension on mornings after large doses of 2 part calcium buffer (without the Mg dose) and on mornings after CaOH was dosed. Depletion of calcium by mid morning could result in recurrence of the symptoms. <OK.> I had considered the idea of calcium depletion toxicity before, but discounted the theory because the clam was sill photo-reactive. I figured that adductor contractility would have also diminished if calcium was so low that it was interfering with either action potential propagation, cell signaling or smooth muscle contraction. <I suppose internal levels could be higher.> I have no idea about the histology of the adductor muscle. Is it smooth or striated? ( I guess this doesn't really matter.) In the past week my snails seem to have been doing much better. This is concurrent with your theory that this this is a chemical problem rather than a biological one. If I had some sort of pathogen in the tank the snails should have been the first to kick the bucket rather than get better. <Does support a chemical issue.> I am not sure, but I think I may now have a secondary protozoan infection. When the mantle of the clam is withdrawn (aka not midmorning when the sun hits the tank after a good shot of calcium) there is now a slight curl to a small portion of the mantle. When the clam is extended, here is no sign of pinched mantle what so ever. Do you think I should try and do a freshwater dip? <Mmm, think I would wait here.> Having decided that calcium depletion is a possible cause (and an issue that needs attention in my reef regardless, I am unsure how exactly to proceed. Specifically, I am wondering about adverse effects of GREATLY overdosing my system with 2 part buffer to increase the Ca levels. Do you know of any trace elements present in 2-part that will reach toxic levels if I am dosing WAY beyond the recommended dosage (as I would have to get levels where they ought to be) ? <I'm sorry but I do not have experience with this.> What do you think? <I think it is worth trying and just keeping a close eye on things.> Thanks again for your ideas and input! <Welcome.> Chris <Mich>

Re: Giant clam malady? 10/8/08 Hi Mich, <Hi Chris.> I wanted to give you a quick follow up Re my T. crocea. <Thank you. It is always nice to get follow-up!> You were 100% right. Last night I dosed more calcium than anyone ought to over the course of 8 hours and brought up my calcium 250 pts (now final concentration of 450ppm). <Yikes! Glad you did it over 8 hours!> The clam was fully opened this morning and has remained open all day. (for the first time in almost 3 weeks!) <YAY! Hope all stays happy and adjusted!> To you I tip my hat! <Glad to help.> Thanks so much for your insightful answer. Without your input the clam would have been chowder. <Yikes! No T. crocea chowder please!> Best, Chris <Cheers, Mich>

Magnesium Dosing 9/23/08 I have been having a difficult time maintaining calcium levels (390ppm). I tested my magnesium and it is at 1150ppm. So it is low. Should I dose magnesium at night like I do calcium to avoid the PH going to high? <It really doesn't matter, dose when it is convenient for you. The small doses this provides will slowly raise your level over several days.> The Kent Marine magnesium makes no mention of time of day or effect on PH. Thank you for your help. Jo Anne <Welcome, Scott V.>

Ugh, These Blasted Test Kits!...And Maybe A Little Kalkwasser Seesaw Effect? - 03/18/08 Yep, admittedly I fell prey to bad test kits, first with alkalinity and then with magnesium. <<Very common, in my opinion>> Here is my issue, 1000 gallon system, my reactor used to be able to maintain Alk and calc at appropriate levels, the test kit I was using (Red Sea as I couldn't get Salifert at the time) <<Do try Seachem's line of test kits…good quality for value>> for magnesium was reading 1200 ppm. Little did I know it was below that by 200ppm per my Elos kit, <<I'm not familiar with this brand/manufacturer…though I do seem to recall favorable comments from Bob re>> and I was using Kalk which was eroding it further. <<Mmm, yes…I'm not absolutely certain of the science behind it, but I believe it is something to do with the addition of Kalkwasser increasing the precipitation nuclei of the water column, thus promoting the disproportionate loss of Magnesium>> Needless to say I fell into this desperate addition of varying buffers to maintain Alk and calcium until magnesium finally hit 1300+ (I'd like to stabilize it at 1400, I'm running Zeo Mag in my reactor and it's putting out 1350). <<I think it likely the reactors and the Kalkwasser additions are battling each other…probably best to discontinue the latter>> So, long story short, tested my levels last night, Mag 1300, Alk 8, CA 400. My reactor ran all day, is well tuned in with a pH of 6.5 and Alk output off the scale. I dosed Kalk for a while today to raise pH as it was floating around 8.1 and I wanted to get it higher (dripping maybe 20 drips per minute, in a 1000 gal system I thought it was just about right). Tested Alk tonight and it was 7, CA 360 and Mag 1200! <<Refer to my previous statement re the Kalkwasser use>> I do have a little detritus but not a big buildup. I don't understand why I can't nail down solid levels. I increased the CA reactor output and it's a steady stream, but I am really wondering at this point if I am not best off adding another CA reactor. <<This would be preferable to the Kalkwasser additions>> I do have heavy SPS but I can't believe they are sucking that much calcium. <<If exhibiting heavy or even just "good" growth their demand can be considerable>> I am beginning to wonder if I am not in some type of runaway supplement nightmare <<…yes>> (I add all according to directions), but the sheer fact that Mag fell by 100 in a day (per my Elos test), indicates to me stop dripping Kalk, use Seachem's buffer for pH if need be, and dose mg according to directions until it stabilizes. <<Sounds like a plan>> I don't have any nutrient sinks that I know of (only DSB is a DSB 30 gal trash but it has no detritus in it). Any help is greatly appreciated! <<Stopping the Kalkwasser dosing and stepping-up the Calcium reactor(s) should make a dif…oh!..as well as a large water change to help bring all back in "balance." Regards, EricR>>

Water Chemistry Help!  Mg... KH interaction, fixing  3/15/08 Good Day Crew!! <Hello again.> As suggested we bought a magnesium test kit and tested our magnesium...it was around 1000 yesterday and I'm not sure if I am just having a hard time understanding or reading the directions on the tech-m bottle from Kent, but it says " test magnesium in aquarium, then add tech-m at the rate of 1ml per gallon aquarium capacity per day to bring the level to between 1250-1350ppm, this will raise the level by 18.3 ppm per day". Fine...so does that really mean that for my 180gal I have to add 180ml? Seems like A LOT....?! <Yes, one ml per gallon is correct as per Kent's directions, it does take quite a bit of this product to get the magnesium up to an acceptable level, less of it to keep it there.> Not sure, anyways I only had 70ml left so I put it in slowly yesterday (around 1:30pm) our levels were: dKH 14,phosphates 0, nitrates 30 (water changes needed more frequently to lower right?), <Yes, to aid the reduction of KH also.> calcium 360, magnesium 1000, ph 8.2, total Alk 5.5 mEq/l. <Test your mixed up water for these levels also to be sure the levels are more balanced (lower KH, higher Ca and Mg).> After I tested I added the equiv of 100gal of the tropic marine calcium powder, topped up my sump ( right now its just tap water but we have an R.O unit...is going to be installed when we move in 1.5 months) added the 70ml of magnesium and that's it. <Test your tap water for nitrate also, if it is the source then water changes will do you no good in that regard.> This morning around 10:30am I tested again... magnesium 1000, total Alk 5meq/l, calcium 340ppm, dKH 16, nitrates 30ppm, ph 8.2 and then changed to 8.1 by the end of testing. This morning I fed the tank some Cyclops, rotifers, brine shrimp (all 3 of those mentioned were frozen) and a small amount of phyto (bottled). Any suggestions to make things equal out? <You need some water changes to bring down the KH. With a good quality salt this should also raise you Ca a bit, as well as Mg. Do test your makeup water, I do suspect the tap water could be making your KH numbers so high.> I'm having a hard time interpreting the results, kind of late but we're just really starting to get into the testing and real understanding of water chemistry..... and yes, the purple up is gone!!! <Great! Keep reading and testing, you will get the hang of things with vigilance and time/experience. You are not too far off here. The magnesium definitely needs to come up, 1250 or a bit more. Also, bring your KH down, as well as the nitrate. Good luck, Scott V.>

Magnesium Gluconate 10/27/07 Dear WetWebMedia-Team, I have a question on raising the magnesium level. I have read on your site that you can raise calcium levels by adding calcium gluconate instead of CaCl to prevent chloride from accumulating. Can one analogously use magnesium gluconate to raise the magnesium level if necessary? <I don't see why not. Mg gluconate is just another salt of gluconate.> I am asking because I already have pure magnesium gluconate at home for supplementing pet food and when calculating molar mass I come to the result that it contains approximately 5.7 % per weight magnesium. I am just not sure if magnesium in the form of gluconate could have any adverse effects (if administered to the tank slowly and properly, of course) or if it will stay in the water column at all. <The gluconate is a sugar and so you'll have to be mindful of that. But so long as you're not adding heaps of it at a time, it shouldn't be a problem.> Thank you & best regards, Alex <Best, Sara M.>

Chloride Ion Buildup From Dosing Magnesium Chloride? - 10/04/07 Crew, <<Brett>> I understand that the long term use of calcium chloride as the main means of calcium supplementation is frowned upon due to the potential buildup of excess chloride ions. <<True, though I think this is rare and often limited to extreme cases where the product is likely "abused" and regular aquarium maintenance/husbandry is neglected>> I recently started dosing Magnesium Chloride to correct a low Magnesium problem. <<This is generally a seldom /not often needed adjustment unless heavy Kalkwasser use is depleting the Magnesium from the system>> Does long term use of Magnesium Chloride suffer from the same drawback? <<Maybe...if also overused/abused and frequent water changes are lacking. Magnesium Sulphate might be a better "heavy use" long-term solution but the Chloride form is easier for the organisms to use/metabolize than the Sulphate form, as I understand it...kind of a "Catch-22.">> What about strontium chloride? <<I think an over accumulation/imbalance of any chloride ion should be avoided...but most chemical-balance issues can be rectified with the correct water-change regimen>> What is the best way to raise/maintain Magnesium? <<Infrequent adjustments can be made using simple Epsom Salts (Magnesium Sulphate), but, mainly because the effects of impurities re is unknown, anything more than infrequent use should probably be with a proprietary aquarium product like Seachem's 'Reef Advantage Magnesium' (which consequently, is a "blend" of Magnesium Chloride and Magnesium Sulphate)>> I dose Kalkwasser with the slurry method and use SeaChem's Calcium and Alkalinity supplements per GARF's bullet-proof reef suggested method. <<I am a BIG fan of most all Seachem's product line>> I recently noticed that the SeaChem Calcium supplement that I use to raise Calcium is Calcium Chloride based. <<Yes, this is the most often/easily used "booster" re>> It also contains Magnesium and Strontium Chloride. I am switching to a Calcium reactor and Kalkwasser reactor/top off unit. Is it a good idea to mix Magnesium chips in with the Calcium reactor media to maintain Magnesium? <<My experience re was less than stellar. It didn't cause any problems that I am aware, but I didn't really notice much difference/improvement, which may well be put to the source/quality of the material used (I think there are several options available now). It is worth trying/drawing your own conclusions I think>> As always, thank you for your time! Brett <<Happy to share. EricR>>  

Re: Chloride Ion Buildup From Dosing Magnesium Chloride? - 10/05/07 EricR, <<Brett>> Thank you for your feedback! <<Quite welcome>> I was dosing too much Kalkwasser slurry when my Magnesium level dropped - as you expected and I have since read :-). <<I see>> This coincided with a hiatus to my normal testing diligence so I ended up with Calcium levels in the high 500's, dKH around 7 and Magnesium around 1050. My SPS and Maxima clams were not happy and started fading, so I started testing again. <<Close, daily observation of the organisms in our tanks is a good way to measure/monitor the health and status of/changes to the system>> Over a few weeks I got my levels back in order - 400, 9-10, 1100 (still trying to raise the Magnesium). I am continuing to test and tweak my dosing regimen and trying to do 15% weekly water changes. <<Maybe a larger percentage but less frequent regime would be of more benefit right now>> SPS colors have since returned to full bloom. <<Excellent>> I used Seachem's Reef Advantage Magnesium to raise my Magnesium levels at first before switching to ESV's liquid Magnesium supplement. <<Also a good product>> The liquid supplement was much easier to add since I did not have to try and get it to dissolve first but it is 100% Magnesium Chloride. It sounds like I should be able to get to a point where I only use Magnesium Chloride as a periodic boost so that should be ok. <<Agreed>> I will experiment with Magnesium in the calcium reactor. I am sure that will take months to vet due to the slow nature of the make a change, test for one or two weeks and adjust loop. <<Keep in mind the reactor is for "maintaining" not for "boosting"…>> Do you think that adding Reef Advantage Magnesium to a calcium reactor is a bad idea? <<Mmm, yes… Too much trouble and will dissolve much too fast…best to dose as prescribed by the manufacturer>> Or should I look for a media designed for reactors? <<This would be best>> Thanks again. Brett

Magnesium effect on algae and bamboo shark  - 05/26/07 Hello WWM crew,    <Dave>   Great site, the aquarist bible. I have 2 questions that I've been researching, that I was hoping you could help with. I have been having a problem with algae in my 100 gallon tank. Not sure if its hair algae or Bryopsis. I use RO/DI water doing water changes, 5 gallons a week. I also added a PhosBan reactor <For? You have measurable amounts of soluble phosphate? How much, from what source/s?> with Rio <I would "watch" this pump... and would NOT run with a shark present... due to ferrous/Ampullae of Lorenzini issue> 400 pushing it, about a month ago. Lighting consists of 2 150 watt halides and 4 55 watt pc's. Halides stay on for 10 hrs, pc's for 12hrs. Long story short, algae is taking over. I try not overfeed flakes or Mysis once a day, alternating between the Mysis and flake daily, for 8 fish. I was reading here:( http://www.reefcentral.com/forums/showthread.php?s=&threadid=1113109&perpage=25&pagenumber=1 )   that a good prevention for algae is to boost your magnesium. <Mmm, no... not unless the proportion is off...> Any thoughts on this? Also I have a month old bamboo cat shark that is temporarily in this tank until i move him into a 300 gallon pond designed especially for him. Will the magnesium boost effect him? Thank you for all your help. Thanks Dave    <... keep reading. Bob Fenner>

OOOooops.  HIGH Magnesium!! - 4/28/07 I wonder how many Chemistry related questions start out with the title of "Ooooops." I'd imagine not as many as should...lol. <Indeed…> Well, I did something stupid and am hoping for some advice. About every 2 days, I mix up 2 or 3 gallons of Kalkwasser. Let's see, today's Friday so it must have been Tuesday. Yes, on Tuesday, I grabbed one of my gallon jugs, poured it into my drip jug and set it up dripping into my sump over night. This morning, I had to move a couple empty mixing jugs for some reason. Low and Behold, there's the empty gallon jug that I used Tuesday night....labeled....Mg Supplement!!!!   <Uh-oh.> Yep, I dosed almost an entire gallon of Mg Supplement (Randy Holmes recipe using just Epsom Salt) instead of my jug of Kalkwasser.  Well, I rushed to my tank and everything appears to be just fine. In fact, everything actually looks really good....lol. <Good sign.> Anyway, I realized this right before having to leave for work so couldn't do anything about it. I'm home now and just tested my Mg. I'm not sure how to read the results. I am using a Salifert test kit. Using the 1 ml syringe, I drew the Mg-3 reagent in as instructed. I then emptied the entire contents and still needed to add more. I drew the reagent into the syringe again, filled the syringe the same amount I did the first time. From this I added until I got my color change. Holding the syringe tip up, I'm reading the plunger at .78. So, the first full syringe puts me at 1500 ppm. .78 would put me at 330 ppm. Does that mean that I'm at 1830 ppm? <Yes, that is correct.  The relationship is linear and additive.  Just add the results from each syringe together.> Normally, I try to keep my Mg at about 1330-1350. Obviously, I'm just a tad bit high!!! <It's not so bad.  A reasonable range is 1300-1500, so you are not ridiculously above this.  One would wonder how high the sulfate levels are also, although this should also not be in a problematic range.> Any suggestions on what I should do? <If nothing is reacting badly, I would not panic.  Change water as usual and keep checking Ca levels.> Any advice would be great!!!  What are the effects of HIGH Mg levels? <There are not a lot of known effects of high magnesium, it can vary quite a bit.  The most likely victim would be the snails, as the magnesium acts as a muscle relaxant.  If your snails seem particularly lazy, you might want to accelerate water changes. Links you may have already read, but in case you haven't: http://www.wetwebmedia.com/mgmarfaqs.htm http://www.wetwebmedia.com/alkalinity.htm http://www.advancedaquarist.com/issues/oct2003/chem.htm It should be fine.  Alex>

Mg & MACNA  4/17/04 Hello,         I've recently discovered that  the Tropic Marin salt mix I'm using only has 960-990 ppm of Mg. So I want to  raise it to 1050 ppm in my make-up water, before adding to the tank in the  form of a water change. I already have Epsom salts, but recently read an article  about how sulfate levels can get too high, via the Mg  sulfate. In this  case is it alright to use the Epsom salts long term/permanently? <Is almost always no problem> Or  should I use Mg chloride? <Could use... though there is some downside to excess chloride as well... Again, either/both are not really problematical>    What's the acceptable range of sulfate in a marine tank with live rock, red headed neon Goby and xenia? <A healthy aquarium (or. seawater) typically has sulfate levels of about 2700...> Is there such a thing as a sulfate test kit made for this hobby? <Mmm... not made for aquariums per se as far as I'm aware... but there are such assays... see Hach's, LaMotte's et al. sites...> I  also know that long term calcium chloride use can cause problems. Does the  same potential problem exist with  Mg chloride use? <Mmm, yes... but once again, with serial dilution (regular water change outs...) not simple addition, top-off... not a problem>         Also, how do I get my hands on  the MACNA XVII, Expanded Horizons video? Is it for sale? Is it for  free? Is it available at my local library? <Maybe... Please contact the "parent" organization (MASNA) re: http://www.masna.org/>      Thanks for all that you've done to help make  this fun hobby a success,   Greg <Welcome. Bob Fenner>

What's the Diff. between Magnesium and Molybdenum?   2/26/07 <Greetings, Mich here.> Molybdenum and magnesium... are they diff. substances? <Yes.  Chemically notated MoO42- and Mg2+ respectively.> <<Mmm, just the elemental Mo and Mg symbols for these? RMF>> I think it is a yes...or is Molybdenum just another form of magnesium? <No.> Because Red Sea produces...Molybdenum...they don't produce magnesium...and Seachem sells magnesium but not Molybdenum.... isn't it weird? <Mmm, no stranger than anything else.> What's the effect of Molybdenum to reef tank? <Possibly a micronutrient.> Which is more important ?? <Magnesium.> I am using magnesium only...should I put in Molybdenum too? <No.> What's the effect to my corals if I used Molybdenum too? :) <As far as I'm aware the science isn't well understood.  RMF any comment?  -Mich> <<Not necessary in any system I've ever read about, encountered to add this micro-nutrient... is only necessary in very small amounts... supplied by salt mix, foods... RMF> Reef tank problems Calcium, Alkalinity, Magnesium - 2/20/07 Hello, <Hi Bryan, Brenda here> I have a 90 gallon saltwater tank that has been set up for almost eight years. For the first seven years I used 4x96W PC with actinic/white bulbs and never had any major problems. My tank had a lot of mushrooms, polyps, xenia, leathers and a few hard corals like cup corals/pagodas. Then I switched to 250W MH lighting with 14K bulbs. Over the course of 18 months I lost almost all of my coral. I found out that my calcium and alkalinity were really low (due to the MH lighting I guess). <No, Not the lighting.> I had been dosing just Kalkwasser up to this point, which apparently wasn't enough to meet the needs of my reef. <Are you testing for Magnesium?> I have since started using B-ionic two-part solution. This has helped my calcium and alkalinity to some degree but I cannot seem to keep the Ca over 380. My Alk is usually around 3.8 to 4.2. I had acquired some new corals awhile back (polyps and Montipora) and they are starting to look washed out and the polyps aren't opening up much now. My tank has very little coralline and what is there looks really washed out. I'm not sure what the problem is, but I'm about to give up on MH and go back to PC since I never had trouble before. My MH lights are 8 inches above water surface and I run them 10-11 hours a day. Do you think my tank is getting too much light or not enough? <Not a lighting issue> The bulbs are only a few months old (ordered from Hamilton). Why can't I keep my calcium above 380? I've even been doing double doses of B-ionic and it doesn't seem to make much difference on the Ca levels. I started adding Fiji Gold on top of Kalkwasser and Bi-ionic. My sand bed is only about one inch deep and is kind of old. Is there a possible buffering problem? I do 7-10 gallon water changes every 5-10 days using r/o water. <Sounds like you are low on Magnesium.  Purchase a Magnesium test kit.  Magnesium should be in the 1300 - 1500 range.  Here is an article to help you understand the importance of Magnesium, and its relationship to Calcium and Alkalinity.   http://www.advancedaquarist.com/issues/oct2003/chem.htm  > Any thoughts would be appreciated. -Bryan <Any time Bryan!  Good luck!  Brenda> Magnesium and Sulfate Question - 2/8/07 Hello! <Hi Chris, Brenda here> I've been struggling to get my Calcium levels to rise and stay at a good level.  I seem to be averaging about 290 ppm.  My Magnesium level is about 1140 ppm at the time, and I was told to raise this level so that it might allow for a higher Calcium level to be maintained. <Yes, Magnesium should be in the 1300 - 1500 ppm range.> I've been using calcium chloride (1/2 tsp mixed into top off water) to supplement for Calcium while maintaining good alkalinity levels. <I hope you are not mixing your calcium and alkalinity supplements together in your top off water.> I use this almost daily with the results averaging the levels mentioned above, and I wouldn't know just how the chloride is reacting in my tank.  I'm running a 75 gallon reef tank, and my question for now is can I use Epsom Salt as a means for a Magnesium supplement, and how does Sulfate react in the tank, can it become toxic?  You're website has been a world of help, answering most of the questions I ever have. <Thank you for the positive feedback!  Yes, you can use Epsom Salt.  Here is an excellent article written by Randy Holmes-Farley.   It has a lot of useful information.  Also read the links provided within the article, and check out the calculator for proper dosing.    http://reefkeeping.com/issues/2006-07/rhf/index.php > Thank you so much for the time you all have given to help others.   Sincerely, Chris Brant <Your welcome, I hope this helps!   Brenda> Re: Ich, Low pH, Low Calcium, Possibly Elevated Magnesium    1/17/06 <Hi Jennifer, Mich here again.> Thanks.. I'll try the baking soda.. I got a reef testing kit the other day. all is great except the calcium is low..300. <This may be contributing to your snail/limpet problem.  I suspect your magnesium level is also elevated, if your calcium level is low.  The magnesium may be acting as a muscle relaxant, which may explain why the snails are alive, but the not moving.  Adding calcium will lower the magnesium levels and may remedy the situation.  Try to increase your calcium levels up to around 400 mg/L.   Now I have another problem (it's always something, huh?), ok, here goes.. I've got a 10 gal QT set up with a clown, a firefish and a damsel.  I got ich in my DT so I put all fish in the QT and I'm going to run the DT fallow for at least 6 weeks.   <Very good.> They've been in the QT for a week and the damsel is not doing well. <Sorry.> Here's what I've done. I treated with CopperSafe and have been testing water daily. <And the levels are in the recommended therapeutic range?> I've been doing daily water changes (up to 50%) to keep ammonia, nitrite and nitrates down. Nitrites at .25, all else at 0.   <This is important.> Don't have any kind of bio media in there since whatever I have in the DT might have ich and I don't want to put that in the QT. <No matter, the copper will kill off most of the biological filtration anyway.> The damsel's color is not good, not eating, gills pumping and she's not really swimming.  Could the CopperSafe (chelated copper) being doing this to her? <More likely the ich.> Any thoughts on how to save her?   <Not really much you can do but keep the copper levels in the recommended therapeutic range, keep the ammonia / nitrite/ nitrate levels in check via water changes and give her time.>   Thanks! <Welcome!  -Mich>

Re: Ich, Low pH, Low Calcium, Possibly Elevated Magnesium   1/19/07 <Hello again Jennifer, Mich here.> Could the mg/calcium be the reason I just lost a porcelain crab? <Hard to say, there are many possibilities.> The other one's not looking all that great either.  The coral banded and green crab are bit lethargic as well. The only thing moving are the algae conchs. <Can you test your magnesium levels?> I've been adding Kent's liquid calcium everyday  but I'm afraid of adding too much. Any advice as to how much to add? (I don't have a Kalkwasser) Test results today were 340. <I would aggressively follow the directions.> As for my QT my damsel seems to be hanging in there.  I'm just going to have to reside myself to daily water changes.     I do have a few more questions if you would be so kind...since I am new to this crazy hobby (yes, one has to be crazy to get into it or you will be shortly thereafter) <Hehe!  We are in agreement here!> I didn't set up things they way I should have (budget issues).   <Usually makes more economic sense to go slowly.> I currently have 60# of crushed Florida coral in my 55 gal and want to switch it out for sand (after I work out above issues). <You can do this but you don't need to.  Can keep it as is, or add sand.> Should I do this all at once, in sections; if so should I remove the inverts due to the nitrite spikes? Also, I want to add live rock. <Oh!  You don't have any live rock?  This would be the first thing I would do.  This will greatly increase your filtration and overall stability.> How much for a 55 gal? <At least 55 pounds, 100 pounds or more would be better.> Does it depend on the livestock? Thank you for all your help and expertise!!!!   <Welcome!  -Mich> Jennifer

Re: Ich, Low pH, Low Calcium, Possibly Elevated Magnesium, system improvements...   1/19/07 Ok, so first order of business.. I'll get some live rock...I just bought a CoralLife protein skimmer.. hopefully that will help with some issues.   <Skimmer and live rock will both greatly benefit your tank.> I tried to find a magnesium test today at some of the LFS and no one had any. They all said "They aren't very reliable".   <Hmm, interesting.>   Thank you for all of your invaluable advice and help!!   <Welcome!  Good luck with your setup!  -Mich> Jennifer  P.S. I'm sure you'll be hearing from me again!! Epsom Salt in Main display -- safe?  - 3/1/2006 Hi Dear Crew members,    <Cam>   I really appreciate your existence and help given to all of us in this fantastic hobby.    <Welcome>   I have a Redbar Anthias, measured 3 inch and  2 days ago, it got a pop eye on its left eye. The pop eye got bigger by the day & I am bent on dosing Epsom Salt as suggested by your web sites after goin through the FAQs. Before I do it, I need some clarification. so, please help.    <Will try, am trying>   Beside the pop eyed Anthias, the main display houses Emperor angel (6 inch), Regal angel ( 3 inch), Red Shoulder fairy wrasse, Cleaner wrasse ( this baby has been with us for more than 1.5 year, it eats pellets & flakes), Coral beauty Dwarf angel, Firefish goby and one SUN Coral. I suppose Epsom would not affect them negatively?    <Not in small concentration, no>   Question is: Is it safe to dose Epsom Salt in Main display? Some FAQs advised to take patient out into QT rather than treating in Main display, but some said OK with main display. Please help me by one more reassurance that it is OK to dose Epsom Salt in "Main display tank"?    <Is okay>   The dosage is one table spoon per 5 gallon and repeat every 3 days, if eye is still popped... is this confirmed?    <... I would cut this dosage by half... a level teaspoon per ten gallons of actual water volume, AND no need to re-treat unless you change water out...>   Sorry for asking as I have not done it before. so got a bit cold feet. Hope you understand!      Cheers!   Best regards. <Do. Bob Fenner>

Please Help! -- Mg damage to corals? Sclera. health - 2/28/2006 Hi Crew, <Greg> I hope I am worrying needlessly, but I am concerned I might have an unknown coral predator or a water parameter problem with my 180g reef.  My main concern is one Acropora with approximately a pea-sized exposed skeleton near the base of one branch and ?" of skeleton exposed on one tip.  A brown mucous-thread-like substance covered the Acropora, with dead tissue trapped in the bottom of this mucous net.  I siphoned-off the mucous and dead tissue, cut off the dead tip of one branch, then dispensed a tank water + Lugol's solution over the remaining bare skeletal areas.  I just fear that this area of necrosis might be spreading.  This Acropora is placed approximately 8 inches from a 7" Crocea clam (which occasionally produces a similar-looking mucous-like "net" near the byssal opening).  So I am unsure if the Acropora coating was from the Crocea or if it was produced by the coral. <Mmmm> Two days prior to this happening I did move a rock that was attached to this Acropora and one tip was broken off the Acropora.  This has never been an issue in the past as new flesh would cover the exposed skeleton within a week and new branches would form.  Possibly this initial stress is what led to the current tissue necrosis. Current water parameters: Temp=77?F, Salinity=1.024, pH=8.1, alk=3.2 meq/L, Ammonia=0, Nitrite=0, Nitrate~1ppm, Ca=440ppm, PO4={below meas. Limits}, Silicate=0).  I did also increase temperature on my heaters from 76?F to 77?F a few days ago.  I performed a 32g water change at the same time. A little history… About two weeks ago, I noticed that all of my Montiporas were becoming much lighter in color.  I was not overly concerned because they have lightened and darkened in color several times over their 2 years in my tank and they continue to grow well.  Although water parameters have always remained within acceptable ranges previously, my salinity dropped from 1.025 to 1.022 <This is a huge difference> over the course of a day just before the Montiporas changed color a few weeks ago.  A snail had stuck my makeup water float switch in the "on" position for a day, flooding my 100g refugium and diluting the water with RO/Kalk mixture. <No fun> My pH measured 8.2 so I was only concerned about the sudden change in salinity (makeup water flows at only 10gpd).  I removed 10 gallons of tank water and slowly added 10 gallons of very high salinity water until tank salinity measured 1.023.  The following day, I repeated this procedure until the salinity reached 1.024.  All fish, corals, clams, other inverts appeared to be unstressed so I assumed that worst case, this might have induced a temporary color change in the Montiporas. <Takes a while to show... weeks, months> Since my alkalinity and pH have always remained near the low end of acceptable (pH=8.0-8.1, alk=2.5-3 meq/L) despite using a Kalkwasser reactor for top-off and the addition of Na2CO3 and NaCO3, I bought a Mg test kit to determine if a low Mg level was partially responsible for low alkalinity (Ca=440 ppm).  Mg measured 1,140 ppm <Close enough...> so I mixed 10 teaspoons of Seachem Reef Mg in 1 pint of RO water and dripped this into the pump intake in my refugium.  An hour later I repeated this.  According to Seachem's label, I would have needed to repeat this process a few more times to reach the desired 1,300 ppm but I noticed another Acropora (near the return line) with mucous-like threads waving from its polyps.  I was concerned that I might have changed the Mg level too quickly so I made no further changes to the tank for the next two days. <Good> I did continue to noticed these "mucous threads" waving from the Acropora polyps at times.  This is a different Acropora than the one that is currently displaying tissue necrosis.  Could dosing Mg in this way cause tissue necrosis in Acropora? <Possibly a factor, not likely "the"> This particular coral is not in direct flow of the pump return line. One Montipora has completely bleached (although polyps are visibly extended) but I did move this coral to a lower light area of the tank when it initially began to bleach.  All other corals (4 Acropora, 1 birdsnest, 1 open brain, 1 pineapple coral, hammer coral, zoos, star polyps, mushrooms, Alveopora) appear to be doing well.  Even the Acropora that had previously produced the mucous-like threads now appears normal.  All inverts appear unstressed as well. What should I do about the Acropora with the tissue necrosis - is there a way to reverse this spread?   <You likely have> If the necrotic area continues to grow, I assume I should frag the coral to save the remainder - correct? <An approach. I would move this colony to another system, or even shallow, brightly lit sump first myself> Do you think this in contagious (e.g. should I be doing anything to protect the other corals in my tank)?  Unfortunately I do not have a picture to send yet, but I can follow-up when I return home tonight if needed. Thank you in advance for your help!!! --Greg <I doubt you have a pathogen at play here. Very likely the bit of trouble you've observed is/was due to the change n spg... I would not over-react here. Bob Fenner> Re: Please Help! -- Mg damage to corals?  - 3/1/2006 Bob, <Greg> Thank you so much for your input (or at least putting my mind at ease) -- and for taking the time to read my email.  I will continue to watch this Acropora, but no additional skeletal areas appear to be exposed tonight. <Good> I refer all of my fellow reefers to the WWM search for answers to their questions.  You and the WWM crew offer an invaluable service to aquarists! --Greg <We're very glad to share. Bob Fenner>

Epsom Salt/Magnesium    2/17/06 Dear Mr. Fenner & Staff, <James today.> I recently had a professional lab run some test on my water. Alk- 3.0 CA- 348 PH- 8.2 MG- 880 Sal- 1.026 (my reading) Phosphates- 0 My question is my Magnesium seems to be very low in my 90 gallon reef tank. I have had a problem with slow growth and was wondering if the low numbers on the Magnesium could be the culprit. <Not the only.> I called up the tech support at Seachem and she suggested that maybe my salt was low in magnesium. I use Tropic Marin pro reef and don't believe that to be the case. Water changes are performed every two weeks religiously. I went out and bought a Magnesium test kit and Seachem Magnesium. After the reading the label I would need a few bottles to get me back in the 1,000 mg range. Would it be possible to use common Epson salt. <Yes, might consider the Pharm grade.> Thanks once again for all your help! <You're welcome.  James (Salty Dog)> High Magnesium Level 01/19/06 Hi Guys <<Hello Tom - Ted here>>. Bob Fenner said my problem with declining coralline algae maybe due to a Mg imbalance. The Mg level is off the chart measuring 1500 +. The Ca is at 430. I couldn't find any article to say how to lower the Mg. <<Lower the magnesium level by doing water changes and quit supplementing magnesium. Please read this article on alkalinity by Anthony Calfo (http://www.wetwebmedia.com/alkalinity.htm).>> Is 1500 + too high?<<Yes>> If not I'll work on the possible predation problem that he suggested. Thanks for all the help. Tom   <<You're welcome and good luck - Ted>>

Magnesium In A FOWLR - 07/13/05 Hello, <<Hi>> I was just reading the article on alkalinity and a Kalkwasser stirrer. It mentions the magnesium level should be 3x that of the calcium level. <<Yes...about.>> I use natural seawater.  So I need to find a magnesium test kit and start adding magnesium right? <<Not necessarily.>> I test for nitrates, kH, ca, ph, nitrites, ammonia, phosphates, salinity. <<ok>> Is there anything else I should be worrying about in my FOWLR tank as magnesium is a new one to me? <<I doubt you need to worry about the magnesium, really.  As this is a FOWLR tank, you don't have a large quantity of calcifying organisms (e.g. - SPS/LPS corals).  If you are applying frequent partial water changes you're likely supplying all the magnesium this tank needs.>> I supplement trace elements as well. <<Another waste of money in my opinion.  Again, the water changes will supply.>> Many Thanks, James. <<Regards, Eric R.>>

Magnesium...A Few More Questions - 07/14/05 Hi Eric, <<James>> Thank you for your reply and help. <<My pleasure>> I just want to clarify and get your thoughts before I go and purchase a Kalkwasser stirrer and top up system. <<Alrighty>> For my FOWLR system of around 1600 liters (400 gallons I think)<<nice>>, I need to keep calcium levels 350-450. <<Actually...anything "around" 350 will likely do just fine for your purpose.>> This stops the buffering capacity from dropping so quickly, so less need to add so much buffer.  Am I correct? <<Calcium is but ONE of the elements supporting alkalinity...calcium/alkalinity is an oft misunderstood relationship which can be confused by the best of us...Anthony Calfo offers a very good explanation in lay terms here: http://www.wetwebmedia.com/calcalkmar.htm>> I do have a 5 inch DSB as well. <<Excellent>> My kH falls very quickly so I am constantly buying Kent SuperBuffer and kH test kits. <<Honestly, I think you would have fewer troubles if you used a proprietary salt mix (IO and Tropic Marin get my votes) over natural sea water.  Aside from the risks of disease/parasites associated with using natural sea water, it can exhaust its buffering capacity quite fast...as you are experiencing.  If you are determined to use natural sea water you will need to resign yourself to constant/frequent testing and addition of buffers...or even more frequent water changes.  The addition of Kalkwasser you are contemplating is an excellent way to dose calcium...and will support alkalinity by tempering acids...but does little to add earth elements to the buffer pool...all of which could be handled with frequent partial water changes using a quality synthetic salt mix (hint! hint! <G>)>> You say trace elements is a waste of money. <<In my opinion, yes.  Snake oils for the most part.>> Is there anything I should be adding to benefit the live rock and the fish? <<As previously mentioned...frequent partial water changes...>> Someone said iodine?? <<Can sometimes be beneficial...follow instructions/use prudently.>> Many Thanks, James. <<Regards, Eric R.>>

Re: FIN ROT & USING MAGNESIUM Dear MacL the site you put me on to is about nitrates, is this what you where talking about or a mistake. <Hey Chris, if you look down into the discussion you'll see where calcium, magnesium and alkalinity fit into the balance as far as nitrates go.  More importantly is the discussion about how they all fall into balance.  I just got through rereading Martin Moe's book. Man does he have a lot of wonderful things to say but the important part is that saltwater is a balancing act.  Let me attach what Rusty said to this email so you don't have to go searching for it. Let me know if it helps you. MacL Ta Chris

Re: FIN ROT & USING MAGNESIUM Hello WWMCrew, <Hi Chris, sorry for the delay I've been at MACNA, so wasn't around to answer.> MacL your info has given me a more insight into what's going on, so if I do more water changes to get my levels closer then bump the levels up with powders at the end. <Right!!! The idea is to get your tank into balance and then adjust what you feel necessary but always achieving balance.> What water would you use I can get RO salt water or fresh salt water both are from LFS shops. <It depends on what you are trying to achieve.  RO salt is salt that has everything taken out of it then the chemicals and traces put back in with the salt. Natural ocean water is just that.>  I still cant get my head around not using additives like reef plus iodide strontium and so on, what do you and Andrew use in your tanks. <I use a lot of additives Chris its just that I test very carefully.  The one thing I never fail to use is Kalkwasser because I find it very helpful to my tank balance.> Yes I will get some all-rounder meds for the fin rot, do you know about Melafix if so will this do the job. <Lots of people like Melafix, I'm always very cautious with meds period Chris.  Good luck and keep me up to date MacL> Thank you for making this so simple Chris Low magnesium and rising calcium levels 5/26/04 I hope you can help me determine if this is a problem or not. For the last several months, my magnesium levels have averaged around 1080. <this is honestly fine if your calcium is 350-400ppm... too many hardcore reef aquarists advise higher numbers (unrealistic) without reckoning the tanks likely lower daily demand for either said element>> I added 20 mgs every couple of weeks to the 75 gallon reef and called it good. My Ca tended to hang around 400 or so, but has always fluctuated somewhat. <no worries... but do consider a calcium reactor for an upgrade to improve upon this> In the last four weeks of testing, my calcium levels have been climbing without adding any of the usual SeaChem calcium additive I used to add weekly. <Hmmm... dissolution of aragonite sand? Is your pH dipping lower than usual at night at the same time. Perhaps the problem> In fact, last test it was at 460 which is quite high for this tank. <agreed> The dkh hangs around 8.3 and is pretty stable. <very fine... especially in light of the higher Ca> My question is are the low mg and high and climbing ca related? <not likely> Should I worry about either? <perhaps not... if you do regular partial water changes (10-20% weekly minimum rather than larger monthly ones) then all well IMO> I use RO water and do about 10-15 percent water change per month. <a modest/light water change schedule that will keep you at the mercy of a see-saw chemical additives dynamic. Do consider a calcium reactor and more water changes> Coinciding with this has been bleaching on 1 of my Acropora. I do not know if this is related or not. Any thoughts? <tough to say on the Acro... many possibilities> Thanks, Sarah <best regards, Anthony>

Water movement and magnesium -3/19/04 http://www.thatpetplace.com/MainPro/itemdy00.aspx?T1=F78+0062+0099 Pauley! I'm still at it. I looked into some of the companies here on the Cape, (one looked pretty good, but I'm holding off, I'm stubborn!) <A big and could be an expensive decision. Take as much time as your animals can take> in the meantime, I'm trying to solve some of the obvious probs for myself, like, water movement. <Excellent, Pam> There are so many pumps and other "water movers" out there I'm having a bit of a time deciding. <Understand> What do you think of this small pump? <Aquarium Systems Jet series are well regarded and respected. I would go with some of their larger pumps though. I remember you having a very large tank> I thought of  buying  4 to 6 of them, and placed in tank in strategic areas pointing at each other to create a constant movement. <Excellent but maybe a bit bigger pump?> I suppose I could hook them up to a device that turns them on and off. <No need. You could though> I have so many dead areas in the tank, and this can't be helping the cyano. <Exactly. You make me happy with your new found knowledge> I've had the lights off in the tank for 2 days now. Just letting in the daylight. It will have to do. <OK. Likely won't affect the growth of the cyano though. It can grow with minimal lighting sources. May help though> I'm bringing the salinity up bit by bit, today it's at 1.023. <Excellent, you> I'm looking for a good ph tester. I do have a LaMotte test, but it's the "matching color" type. Very hard to read! ,I am not a big fan of those either> Sometimes I think it says 7.5 and sometimes I think it says 8.0. I can't figure it out. The dKH is back to 7.8. <Yay!!!!> Tell me Paul. I know you told me NO MORE DOSING, <Right> but,..........I was reading about low magnesium levels possibly contributing to low ALK and Ca levels. <Not with the amount of water you are now changing. I don't think it is possible.> I DO have a magnesium supp., should I add some? <Nope. Unless you can test for it to ensure it level and necessity for dosing then NO! >And what depletes magnesium in the first place? <High Alk and PH are a couple of items that can lead to magnesium depletion. Some say high rate of growth ini coralline algae will rapidly deplete magnesium as well. None sound like issues  that relate to you.> Okay, I've probably picked your brain enough for this mailing. I did send an email to the others at wetweb, but you always respond the fastest (pressure!) <I am slow in good ways> so, here I am again, at your door, asking more! <Not a problem. Here I am trying to give you answers. Will talk shortly. ~Paul> Thank you

Low Magnesium 12/10/03 I have a question for you. Recently my tank has had massive reduction in magnesium. My tank is 120 (uk) gallons with a big profusion of live rock. I have a converted nitrate reductor on tap as a calcium reactor with aragonite media. I have a mixed reef garden tank with the following corals Stonies 2 colonies of cup coral 1 hammer coral 1 Porites 2 Caulastrea colonies (1 fairly large) 2 faviids 1 pavona colony 3 other leathers and polyps Now I know reef gardens can suffer with allelopathy (tempered with frequent water changes), but why is my magnesium so low?  My calcium and hardness are fine. <Hi Jim, Adam at you service today.  My first thoughts are toward verifying the accuracy of your test kit and then to precipitation, and then lastly consumption.  Please do always provide actual test kit readings when relevant (clearly the case for Ca and alk in your situation).  Assuming that your test kit is accurate...  If your alkalinity and/or pH are elevated, this can lead to a precipitation of MgCO3.  This is most likely to occur with the use of very pure Kalkwasser.> The only problem I can nail it down to is the massive (and I mean massive) growth of my purple corallines, they have been growing like mad. I mean plating outwards. I have literally had to break some plates apart because of their size. I am told by my very reliable LFS, that this upsurge of coralline growth depletes magnesium rather than calcium and carbonate? <I have heard this too, but cannot confirm or deny it.> Any of you got ideas? I am supplementing my tank with magnesium supplement now. Mg levels were down to 1080ppm at one point (my fault for not twigging). The out feed from my reactor is around 1450 ppm, which should sustain a reef tank I would have thought. <Be cautious when using such supplements since they can lead to imbalances of other ions.  The supplement is likely MgSO4 and elevated SO4 can interfere with alkalinity measurements.  Adding 10% or so Dolomite (please acquire this from a reliable source, I have seen other things sold as dolomite here in the US) to your calcium reactor medium can help maintain Mg levels without accumulation of SO4. Normal Mg is in the 1250-1350ppm range, so your level is fine, and even at 1080ppm, I would not worry unless you start having problems maintaining alkalinity.  FWIW, CaO and CaOH (kalkwasser) are often fairly highly contaminated with MgO and MgOH which explains why despite the high pH, kalkwasser users rarely have problems with Mg levels.  HTH! Adam>

Magnesium Madness! You guys/gals are the best. <Thanks for the "props"! I'm lucky to work with some great people here at WWM, and we're lucky to have some awesome readers who share their experiences with their fellow hobbyists! Life is good!> I searched around the site and see where Anthony talks about Mg chloride as a cheap way to keep that little nasty Mg at 3 times Ca levels.  My Question, Epson Salt is Mg sulfate.  Where does a cheap basset get the good Mg Chloride?  Heavy Kalk use keeps depleting my Mg.  Ca is 380, dKH is 9 and Mg is 800, So sad.  ESV cost me too much.  Wife would divorce me, but I have no liquid assets.  Spent them all on the Tank.   Thanks for your help.  Epson can give me the Mg, but don't want the fish getting the runs, :). Dosing recommendations per gallon always a plus.  Yeah, I know it depends, but something like a teaspoon raises 1 gallon -20 ppm or something along those lines is very helpful.  Brian <Ya know what? If it were me- and I like keeping things simple- I'd opt for a dry product, like Seachem's "Reef Advantage Calcium", which is relatively inexpensive- about $10 per kilogram, and is easy to use. Or, you can contact a scientific supply store or local high school to see where they order chemicals in bulk...?Alternatively, if you're a hardcore water change nerd like me, you could simply change water on a very frequent (like twice weekly, 5% of tank volume) basis, and let the salt mix be your "magnesium additive". I guess I tend to over-simplify things at times, but I find that water changes usually do the trick, even with frequent kalkwasser use. Hope this inspires you? Regards, Scott F>

Levels question Hi Bob, I'd like to know if I have Ca and Mg low (360 and 1100) in my FOWLR, I have to raise both or It's enough only raising Ca level. I know that their relation is 3 to 1 but Mg additives are very expensive. <Mmm, no. The most readily available, cheap route here is MgSO4, Magnesium Sulfate, aka Epsom Salt> What can you recommend? <What do you mean? Recommend for what?> I won't have these problems if I'd use Tropic Marin salt? tank you very much Lorenzo <Likely not. Bob Fenner>

Reef water chemistry 3/6/03 I picked up a Mg test kit and measure it is about 960mg/L. quite low right?? <not really... just a little low. It should be about 3 times the amount of Calcium and as such is in balance in your tank. A little higher on other (say 400ppm Ca and 1200 ppm Mg) would be nice... but no hurry. Be safe and raise slowly> And in the letter you told me to stop adding supplements and do water changes, I have a 125 gallon, how big is the water change need to be?? <3 water changes of 25-50% each in the next 10 days would be nice> Right now the parameter is Alk-3.2 Ca-280ppm pH 8.2 Mg 960mg/L NO3 5-10ppm Sal-1.022 Temp 78F The corals are doing just fine, and nothing seems to be wrong... <understood... and your chemistry is in balance... just a little flat. No worries.... the water changes will correct that if large enough> should I stop adding Mg still even it tends to be low?? <no low my friend... be careful of the dangerously high levels touted by some hardcore stony coral farmers> And also, what is a good way to change water?? 20 gallons each for 5 days?? Or a 50 gallon change first follow by small ones? Like 15 gallon weekly? <several medium to large water changes will dilute all nicely as per above> Eric <best regards, Anthony> Substrate getting hard 3/4/03 dear Crew: <cheers> I have seen a situation in my tank where i just cannot keep up my calcium level. and my substrate is getting very hard, forming stones... and i have been asking around and people told me that my tank is lacking in Mg. is that right?? <not necessarily... the substrate packs from adding too much Ca or adding it too fast> i have been adding many many alk buffer and ph buffer, liquid calcium and Part A and B additives... but still cannot get it right into the parameter... <when using 2-parts... use no other supplements for fear of skewing their balance. Also, mix the Ca part vigorously before every single use... it stratifies and will get dosed askew otherwise. The extra buffer added was worse than not mixing though> right now, i have only around 8.12-8.19 pH and 3.2-3.5 meq alk... should i dump a bunch of mg additives in and see what happens?? <are you serious? You really can't be. I really hope you are childless with decision-making skills like that. Seriously... my suggestion is for you to pick up a Mg test kit... test your water... and then.... dose additives if necessary up to the recommended level. I am sure this is better and safer> also, when i was trying adding arm and hammer baking soda to try to rise my pH, however, whenever i add it, the pH lowered... why??? <because the chemical soup created in the tank has fostered a precipitous reaction. You need to stop adding all supplements temporarily, do several large water changes in the next 7-10 days, and then simply resume dosing only the 2-part supplements exactly as directed on the package and orchestrated (tweaked if necessary) by water test results. This solution requires reading the instructions on several packages. :) The marine-nazi... Anthony Eric

Magnesium Hey Guys, Can you give me an idea of the relationship between Mg and Ca in a reef aquarium ? <magnesium is involved/influential in calcification... a deficiency can impede rates of skeletogenesis markedly. Our goal is to have approximately 3X magnesium as calcium. A value of 400ppm Ca and 1200ppm Mg would be very fine for a tank dominated by scleractinians> Is there any species that require more Mg than others ? <we believe that some coralline algae require proportionately more Mg than some corals. If you are not running monospecific displays, please don't worry about spiking or unrealistic ideals/highs... consistency would be more important with safe averages> Thanks for the help. Wendell A. Nunes <Happy holidays to the Great White North. Kindly, Anthony>

Ca/ALK and Mg Hi! Finally I receive my mag test and additive. The readings shows something between 950-1000, so I will start to dose some magnesium daily in order to rise it around 1300-1500?? <no need to go that high, my friend. I suggest that 1200ppm Mg is fine and safe/realistic. 400ppm Calcium and 8-12 dKH ALK will be fine targets> There is any advise about daytime to dose it, cautions?  Thanks for any input <simply dose in small amounts and separate from other additives> Carlos D?z <best regards, Anthony>

Low magnesium levels. Gentlemen, I have measured my magnesium levels and they are between 1050 -1100. Calcium levels are at about 350, DKH around 9.  Would it make sense to increase mag. levels to try to raise the calcium levels closer to 400. Using a calcium reactor and night drip of Kalk.  Thanks in advance.  

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