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FAQs about Specific Gravity, Salinity Anomalies

Related Articles: Specific Gravity, Salinity, Product Review Marineland Labs/Aquarium Systems Hydrometer, Part 1 By Steven Pro, Choosing Synthetic/Natural Seawater, Major/Minor Seawater Constituents, Frequent Partial Water Changes

Related FAQs:  Spg 1, Spg 2, , & FAQs on Spg, Salinity: Importance, Science, Measure, Maintenance, & Treating Tapwater For Marine Aquarium Use, Seawater, Seawater 2, Seawater 3, Seawater 4, Seawater 5, Seawater 6, Reverse Osmosis Filtration, Test GearUsing Hyposalinity to Treat Parasitic Disease,

Ideally Spg should not vary measurably... some short term manipulation is not generally deleterious with fishes and some near-shore species of non-fish livestock, but prolonged hypo or hyper-salinity is to be avoided.

Refractometer Regulation       10/5/15
Hello and much admiration of your knowledge and expertise. I hope you might have the answer to a question about my RedSea refractometer. I have used it since onset of my newer (six months) aquarium but as of recent it reads very high. The directions specify to clean using reverse osmosis water and I do so consistently.
<Have you tried rinsing it; as in overnight, in freshwater? >
It seems though whenever I measure my aquarium water the refractometer reads at or above 1.030. However my lfs read the same aquarium water on the same day as 1.025. The tricky part is that if I rinse the refractometer under hot tap water it adjusts back to 1.025.
<Ah yes; salts crystallization in the unit>
My question is whether it is acceptable to rinse (not submerge) the unit?
<Yes; should not cause trouble>
Is this a normal process of getting stuck like a plastic hydrometer?
<Mmm; yes>
The refractometer advertises that it is calibrated for reef aquarium temperature, not that I accurately understand, but I'm trying. I don't want to make any rash changes though, all inhabitants appear satisfied and water tests seem to confirm. The issue of basic salinity is of obvious concern, does this sound like something the manufacturer could assist with?
<Oh yes>
It came with a tool for calibration but also claims to come already adjusted.
<It is>
Do refractometers typically require fine tuning and what indicators for this might appear?
<Good ones do NOT require calibration, nor adjustment>
Your assistance is invaluable. One other silly thing, when measuring salinity or getting a sample for water test tubes is it pertinent to take the water from a certain depth or area (65 gallons if relevant)?
<In modern set ups it is not; as they are circulated such that thermal et al. stratification is discounted>
Or is it accepted to just take the upper layer of water to avoid inserting my hands unnecessarily?
<The surface should be fine. Bob Fenner>

Re: Specification of pH from Nestle Water; now SG     2/4/15
Hi Bob,
A mate of mine and I had a falling out and he was the only guy that also kept marine fish that had an RO.
After the conversation below bnw it is the dry season I need to top up and ran out of rainwater.
Where I am we use well water (not that primitive we have electric pumps) but anyway I think even an RO would struggle.
<Can't tell from here... need analysis, or just trying... there are modules, modular units that can handle most anything... taking out particulates and more ahead of the tris membrane>

Therefore before I try and source other human packaged drinking water what SG are fish generally able to go up to?
<... ?... depends on what species, and to extents, what they've been exposed to>

What are the symptoms of too high SG, all are ok now but a Blueface has blotches maybe due to SG stress but is still swimming and eating normally.
<... See WWM re the subgenus Euxiphipops... not easily kept. To answer your question directly; I would not continuously keep full-marine organisms in higher than 1.025-6 at temp., Red Sea ten percent higher>
Kind regards,
<Keep reading. Bob Fenner>
Re: Specification of pH from Nestle Water; spg f'        2/5/15
Hi Bob,
All the other fish are ok so I do not think it is a disease,
<Me neither; i.e. not pathogenic, but environmental>
here are the parameters in a clear format from Nestle the manufacturers.
I am in a remote place and to get an RO will take several days at best even if in stock about 750kms away.
Anyway I think from your earlier comments the Nestle Pure Life will be the best option.
Any copper will be removed by the Polyfilter.
I must do something quickly.
What do you think, pH seems wide but I have Seachem's Reef buffer which works very well if it drops.
<Only adjust through water changes; and then slowly>
Right now it is spot on at 8.3 Nestle Pure is all go?
pH - 6.5 - 8.5 (seems very wide)
<Is... by two orders of magnitude! How do/did you get these measures? Provided by the manufacturer, Nestle.?
Total hardness 100 - 110mg/l
Nitrate less than 0.4mg/l
Nitrite less than 0.007mg/l
Ammonium less than 0.013mg/l
Manganese less then 0.2mg/l
Calcium 20-30mg/l
Magnesium 7 - 9mg/l
Sulphate 60 - 70mg/l
Bicarbonate 200 - 300mg/l
Chloride 100 - 130mg/l
Nestle Pure Life.
pH - 6.5 - 8.5 (seems very wide)
Total hardness 80 -90mg/l
Nitrate less than 0.4mg/l
Nitrite less than 0.007mg/l
Ammonium less than 0.013mg/l
Manganese less then 0.01mg/l
Calcium 20-30mg/l
Magnesium 7 - 9mg/l
Sulphate less than 5mg/l
Bicarbonate 200 - 300mg/l
Chloride 2 - 4mg/l
<If this is all you have... I would use it. Bob Fenner>
Re: Specification of pH from Nestle Water       2/5/15

Hi Bob,
I thought it better to do something as you are in a far away place, lol, every day it is hot here and the SG was already 1.029
<I'd be diluting this per the SOP on WWM... about a thousandth per day>
and the Blueface was looking bad. Strangely I think I am more worried than he is as he is still eating and grumpy with the Regal Tang who he tries once or twice as day to catch but the Regal is so much faster, the rest of the time they ignore each other. So I purchased some Nestle Pure Life and added enough to hopefully take it down to 1.027. I do not want to take it down too fast not only for the fish but nitrogen cycle bacteria etc
<You are wise here>
I will wait 24 hours and add some more and take it down eventually to normal. I will update you and your readers.
Kind regards,
<And you, BobF>
Re: Specification of pH from Nestle Water, SpG        2/6/15

This morning the Blueface looked terrible with blotches all over him. Today I decreased the SG to normal and the Blueface although looks bad is still eating and grumpy so what I am hoping is that the high SG irritated his skin which secretes more mucus as a reaction which looks blotchy. He is not scratching so I do not think he is in discomfort. I therefore hope in about 48 hours he will be back to normal. The strange but good thing is that the Juvenile Emperor which are normally very prone to blotches is totally normal and so is the Regal Tang the latter would be the first to succumb if this was a skin parasite so I hope....will update.
Kind regards,

need to lower salinity   11/21/10
Hello all. It has been quite some time since I have written in. Obviously I have a question, but first I'll give you all the dirty needed details. I have a 46 gallon bowfront for just about 6 years now. I have 2 TR Ocellaris clowns, one having been with me the whole time. I also have 1 lawnmower blenny, snails
and hermits, and rapidly growing Pulsing Xenia. Please don't cringe when I say this, but of course I have gotten lax in tank care. I do not perform routine maintenance as often as I once did, like weekly-biweekly, but still do it.
I cannot imagine I am the only one who has gotten a bit comfortable over the years with nothing going wrong.
So just got new neighbors, who happen to also be hobbyists. I was delighted because I know no one else. Well, they tested my water for me because they are newer to the hobby and do everything by the book. It turns out my SG is 1.030-1.031, all the while I am thinking it is 1.024-1.025. By "thinking," I mean I use my hydrometer with water changes to make my salt water 1.025.
Clearly it isn't/hasn't been accurate. So maybe it is a good thing my water changes are not as frequent as they used to be, or I would have my own mini Dead Sea or Great Salt Lake.
Now as I understand it, the higher the salinity, the lower the oxygen in the water? Is that right?
<Yes; less solubility>
We certainly cannot underestimate the importance of oxygen! The good news is I have zero ammonia or nitrates. He did say my calcium was maybe in the 600's and should be in the 300's???
<See WWM re>
I honestly was never worried about calcium level because I originally was a FOWLR, so I don't know
what it should be and never tested for it. I guess I believed it was critical for housing corals, and since it was never my master plan to have them.....Fast forward 5.75 years (September), and I'm given like 3 little Xenia frags by that same neighbor, which I thought wouldn't survive, but let me tell you, thriving is an understatement. It is almost like an addiction and I want more, but I promise I am not going there any time soon, esp. given my current, uh, situation. It is quite easy to get sucked in, isn't it? I could sit and just watch it pulse all day long. So my question is, what is the best way to lower my salinity?
<Slowly... take out some system water (a gallon let's say) and replace w/ "just fresh">
I would like to get another fish down the road, and I imagine it wouldn't fare well at such the high SG???
Yes I understand I need to replace salt water with fresh water, but I guess I would like to know how much and how often so as not to endanger my fish and coral? Or do I make salt water for my changes but just at a much lower SG?
If so, at what? And, of course, buy a new hydrometer or refractometer.
Well thank you for your time and expertise. So sorry for the long windedness leading up to my question...bad habit of mine Have a great rest of the weekend.
Tiffani T
<Read here: http://wetwebmedia.com/marine/maintenance/maintindex.htm
Bob Fenner>
Re: need to lower salinity   11/21/10
Thank you Mr. Fenner. I will read the link. Have a good day.
<Thank you Tiff! And I'd like to mention that some of my dive friends share your family name (they live in Oregon)... BobF>

Salinity Changing With Calcium, Alkalinity Additives 8/11/10
Hi there,
<Hello Seth>
I have a question for you all.... I have been adding increasing amounts of Calcium, Alkalinity and Magnesium supplements as I have added more hard corals to my reef tank. Said corals are doing well, growing and healthy as are the soft corals I started with. But, now it seems that the salinity (I use a refractometer) is slowly rising even though I am careful to keep the total volume constant by adding make up water daily. I assume that just decreasing the salinity by removing some tank water and adding RO/DI water is the wrong thing to do, since that would change the relative amounts of other salts? (I have done it twice, as I was above 35 ppt.) What AM I
supposed to be doing?
<What you are presently doing, providing you are not lowering the specific gravity by more than .001 per day. You can also make this adjustment during your regular water changes by making a mix with a slightly lower
specific gravity. How much lower will depend on the size of your tank.>
I will greatly appreciate your input on this. Thanks,
<You're welcome. James (Salty Dog)>

Re: Help....Blue Tang 5/13/10
Hello Dear Mr.'¦..
<It's actually Dr. Neale Monks, but here, you can call me "Neale".>
Today I noticed something wrong with my Blue Tang it is scratching her body with the rocks.. it has a little brown Spot on the body'¦. And I am so afraid for the others.. of the infection'¦specially for my emperor angle fish that still doesn't eat'¦
<The problem is ALMOST CERTAINLY environmental. You MUST buy and read an aquarium book in your language. I honestly cannot offer you any better advice than this. If one fish is sick, you may be unlucky. If two fish get sick, then the problem is with the aquarium. It is crucially important you check salinity, water chemistry, water quality, and temperature. You have given me no information on your aquarium, so I cannot say anything useful.>
Please what can I do'¦.
Some body Advice me to give them a fresh water bath.
all my fish'¦.is that right .....How can I do this correctly'¦
<Honestly, I fear for these fish. You haven't said anything about your aquarium. I'm worried you don't understand what they need. Both the fish species you mention are difficult to maintain. They require expertise. You MUST read. Cheers, Neale.>

Re: Help....Blue Tang 5/13/10
*Hello Dear Dr. Neale*
<Just "Neale" is fine.>
Here is My Aquarium Specification: 850 liters of water with wet dry poi logical filter included Balls'¦.With protein skimmer'¦
<Sounds fine.>
Salinity Between 1.020 and 1.030
<No! This is dangerous! The salinity must be constant. SG 1.025. Not 1.024, and not 1.026. Must be 1.025, every day!!!>
0 ammonia, 0 nitrite
temperature** 27.C
<A little warm; 25 C is best.>
Have 6 Small Blue Damsel
One Yellow Tang
One blue ragger
<Don't know what this is.>
One Emperor Angel fish
One Tomato Clown
<Can I suggest you start reading here:
If you salinity is varying between SG 1.020 and 1.030, then that could EASILY be killing off filter bacteria, and placing a HUGE stress on your saltwater fish. My specialty is brackish water fish, and salinity variation is something those fish handle. But coral reef fish come from the most constant, unchanging places on Earth. They HATE change! Cheers, Neale.>

Re: Help....   where does this go? 5/13/10
so what should I do now
<Do a series of small water changes, perhaps 5% aquarium volume per day, until you get the salinity to SG 1.025. Don't try and do a big water change, because that will stress the fish and the filter bacteria.>
until now you do not tell me what to do first.. to save my tank..
<I have no idea how to "save" your aquarium. If your salinity is varying between 1.020 and 1.030, then that's the reason your fish are sick. Tangs and Angelfish are intolerant of poor aquarium conditions. Provide good water quality and they will feed. If you do not fix the environment, they will get sick. There is no medicine that will fix this. You MUST make sure the aquarium is properly maintained. That means -- among other things -- a constant salinity level.>
I gave you every thing you asked for
<Yes, and I told you what was wrong. Forgive me, but it is difficult for me to help if you cannot read the WWM articles. Cheers, Neale.>

Salinity increasing - from skimming? 2/25/09 Hello Crew, <Hello John.> I have wondered about this for quite a few years regarding salinity increasing over time between water changes. I wonder if this is due to skimming or something else. <Something else.> I maintain my salinity at about 1.025 to 1.0255 before and after water changes etc. During the 2 weeks between water changes the salinity of all 3 of my tanks increase to about 1.026 to 1.0265. <Wow!> I end up mixing my replacement water to around 1.023 - 1.0235 so that when I change water it helps make up for the increased salinity in the tanks after 2 weeks. I even need to under fill the tanks after changing water to then add more fresh to keep the salinity around 1.025 The replacement water is mixed in container for several days or more before using. I add fresh water when needed in between water changes and make sure to top off tanks with fresh water before doing the water change. <Is this RO, pure water? Small amounts of salts in tap water can do this.> I do not return the salt creep back into the tank. The only additive I use is B-Ionic Alk and calcium to the tank. <Likely the cause, it can raise your salinity. If I recall correctly it actually says this on the label.> Any thoughts on this other than Skimming? <Above.> Thanks, John Maggio <Welcome, Scott V.>

Re: Salinity increasing - from skimming? From higher solute addn.s     2/27/09 Scott, Thanks for the reply. <Happy to help out.> I do use city Tap Water and have for years for both fresh and salt tanks. All water from tap into 32 gallon brute and sits for 5-7 days before adding salt for water changes and the make up water from tap ran through a simple filter to remove chlorine. Well I'll be.....I went and re-read the directions again on the B-IONIC label and at the bottom it states that it could gradually raise aquarium specific gravity depending on how much saltwater is removed by protein skimming. <It does, can, will!> I guess the Remora Pro skimmers works too well... Not. Thanks again for your time. John <Welcome.>

Decreasing Salinity   9/27/07 Greetings - <Good Morning> I have an odd situation that I am hoping you can give me some advice on. I've had a 125 gallon acrylic tank set up and running with a 5"?live sand bed, appx. 20 lbs. live rock? and water for about 2 months now.? Specifics are built-in overflow dropping to a sump with a filter sock, pushing through to a protein skimmer that does a gravitational exchange with a refugium containing only Chaeto and some maiden's hair and then pumps back up to the tank.? Tank has two 360 powerheads on a wavemaker timer to provide chaotic flow. I live in Los Angeles, so I buy the Catalina ocean water that typically runs about 1.023SG. We discovered some plumbing problems, so we completely replumbed the system. Before the replumbing, I noticed a lot of salt creep; however, since then, I don't find any anywhere. At some point, I found that the SG in the tank had dropped pretty low - around the low side of 1.021. <Yikes> I mixed up some water with a very high SG (still no livestock in the tank) and, after it aged, put it in the tank. The water went back up to 1.023, so, with everything okay, I moved in some Chromis and a Firefish and about 100 lbs. of live rock.. Now, though, only a few days later SG is back down to about 1.0215. <That is odd. Do you have a protein skimmer? Sometimes protein skimmers can lower salinity. Also, are you sure there isn't salt creep somewhere you're not seeing it? What are you measuring the salinity with? Is your refractometer possibly not temperature compensated?> I'm baffled. I don't see salt creeping out anywhere. No leaks. <Do you have an auto top-off that could be malfunctioning?> Granted, there isn't A LOT of evaporation happening, but why would the SG be dropping like this? <This is strange. It could be your protein skimmer or a top-off issue. Or, it could be the way you're measuring the salinity.> Any suggestions for what to do or how to correct? <Until you can figure out the cause, I suppose you'll just have to keep raising the salinity yourself with high salinity water. I'd question your hydrometer or refractometer first. Get a second opinion from another salinity measuring device. You could also try switching from ocean water to mixing your own salt water.> Thanks - MP <De nada, Sara M.>

Help!! Reef maint.... & Vacations!  -- 09/14/07 Hi, <Howdy> How come disasters always happens when you are away? Don't answer that. <Okay> I live in California and am currently in New York city for 1 week vacation. I have a 175 gal reef tank and I had my neighbor to check on it daily and supplement the auto feeder with frozen shrimps Phytofeast. Yesterday, they noticed that I have an inch of water on the floor and the pump was pushing air into the main tank. <!> We were able to diagnose the problem to my wet/dry where the top filter was clogging causing it to overflow onto the floor. Anyways, they fixed the leak and replenished the water level in the sump with the 6 gallons of already mixed salt water I had sitting around. <Thank goodness for planning> So, they got the circulation back running. But, the top off system was probably dumping RO/DI water into the sum for don't know how long. The SG is now at 1.013 instead of the normal 1.023. <!!> I have a total water volume of about 210 gallons. So, my rough calculation of (0.023-0.013)/0.023*210=91.3 says I have to add salt for 91.3 gallons of water. That is 46 cups of salt! <Mmm, about this, yes> My question is how quickly should I be adding the salt to bring the SG back to 1.023? <Depends on how stressed all looks... I'd start raising a .001 per day if all seems fine otherwise> It will be another 4 days before I get back home. I told my daughter to add in 2 ½ cups of salt to the return chamber of the sump twice a day. <Mmm, should be okay> I am wondering if that is too fast or too slow. Should I also add super buffer as well to maintain alkalinity? <I would leave off with the supplements> I have hard and soft coral, many anemone and fish. My daughter said the anemone and soft corals were looking pretty sad and shriveled up. My clam seems to be gone. Just the shell and scallop stem is left. After 5 cups of salt, the soft corals are looking a little better the next morning. Regards, Sammy <I do hope you can salvage what's left. Bob Fenner>

Rising salinity   1/17/06 Hi,<Hello Ben> I have a question about my 75 gallon reef tank.  The salinity keeps rising a lot.  I know that it will rise because of evaporation but the salinity in my tank is rising I think much faster than it should.  Last night I did a water change and it was 1.028 (which is high but I was planning on gradually bringing it down), when I measured it this afternoon it was at 1.030 and barely any water in the tank was gone.   Do you have any idea what could be causing this and what should I do? <It's impossible for the salinity to rise without adding any salt.  I'm guessing the problem lies in your testing device or how you are using it.  If you are using an Instant Ocean or Coralife you need to be sure no bubbles are sticking to the indicator arm.  This will give you a false high reading.> Thanks a lot, <You're welcome.  James (Salty Dog)> Ben

Re: Rising salinity   1/22/06 Thanks for the response. <You're welcome> I bought a refractometer but my salinity is still really high.  could my protein skimmer or something be taking out a lot of water and not salt? <No, we would all have that problem then.> I don't know if that's possible but that's all I can think of.  If you have any ideas that would be great. <Now that you have a refractometer, slowly remove saltwater and replace with fresh at a rate of .001 per day till you achieve the level you want. When mixing saltwater for water changes do not test salinity until the temperature level reaches the level of your display tank. Lets go from there.  James (Salty Dog)>

Salinity problem 10/31/05 I am starting a 55 gallon saltwater tank up. I have not cured the tank yet. My problem is the salinity. One side of the tank reads too high and the other side reads too low. I have four powerheads running at all times. The temp is perfect, the pH is fine. How do I fix the salinity? Oh and I am using a swing arm hydrometer to measure. <Sounds like you have inadequate water movement. Powerheads are a horrible way to move water in an aquarium, though they are cheap. Please see http://www.advancedaquarist.com/issues/sept2003/short.htm for some great water movement info> Any recommendations will do.. <Hope I've been a bit helpful> New to saltwater tanks <Definitely read everything applicable on this site, and check out the Advanced Aquarist archives as well. Good luck, and feel free to email us with further questions! M. Maddox> 

Cause of problems within 29gal Hey Bob, If you remember my situation, all my fish were dying, but the corals were extremely healthy. I thought it had something to do with the heat, or the large addition of livestock (wrasse, tang, clown, and anemone). I finally found the culprit and it was neither of the above!!!! I am ashamed to say that I missed one of the easiest things in the marine hobby. Remember when I said that the salinity was 1.022-1.023, well it wasn't. After much disgust, I went to the local fish store and took a sample of water for the guy to look at. He tested it for ammonia, nitrate and so on, no problems there, just like my own tests. Well then he looked at the water through a refractometer, and saw that the water was 1.027-1.028. My own hydrometer had become off calibrated and for the past month I have been calculating my salinity completely wrong. I almost passed out from hearing this, notreally but I felt like it. For now on, I will clean the hydrometer more often, get it checked for calibration more often, and maybe look into buying a refractometer (very expensive). A hard lesson to learn for something so simple. Thanks for the help though!!!!! Patrick >> Ahh, a relief to hear of the cause, and solution of your difficulties... High spg is a real problem on several counts... lower dissolved gas, exchange rates, osmotic problems with livestock... A better hydrometer (to check the checker) might be one course for you to take... There are better (good enough) ones of these to be had. Bob Fenner

Salinity level Last week on my 55 gal. reef tank, I noticed some corals looked strange. I immediately checked the salinity it was 1.016- I had lost water on two occasions and replaced with the fresh ro/di water that I keep on hand (no salt added yet) since one of the water loses was at 3 am and the other water loss was before 6 am when I got up I didn't think of the salt. I think that the salinity was low for 2-4 days max. I have lost a sea cucumber, blood shrimp, and all corals look very stressed. It has been a week since I raised the salinity back to normal. Will most corals recover or should I expect the worst. Anything else that I can do to Help them recover. Thanks  Art. Griffin >> Hopefully some, all the surviving livestock will make a speedy recovery... For others edification, you should almost always limit raising, lowering spg to one or two at most thousandths per day in a reef system. Bob Fenner, who says, keep an eye on your water quality in the meanwhile... if it were me I'd install a unit of activated carbon or a pad of Polyfilter in your filter flow path. Harmful SG Change? Hi Bob, I have a 29 gallon reef with 55 lbs of Fiji reef live rock and 20 lbs of live sand. The tank has an Eheim 2213, CPR BakPak 2R, ZooMed PowerSweep 228, and AquaClear 201 running on it. I have a Mandarin, Watchman's Goby, Pistol Shrimp, Feather Dusters, Green Star Polyps, Bubble Coral, and Yellow Scroll Corals in there now. Soon to arrive will be 4 Banggai/Banner Cardinals, 4 Peppermint Shrimp, and 4 Camel Shrimp. <Mmm, sounds like a nice set-up... but I would not place any but one of the cardinals and a couple of the shrimp in this size system> So my question is: how big of a specific gravity change is harmful/deadly to inverts like shrimps? Let's say... in a 12 or 24 hour time period. <In good shape, about 0.001, one thousandth a unit (g/cm3) can be tolerated in the upper teens to near seawater (1.025) range in a day or so... Please read: http://www.wetwebmedia.com/spgfaqs.htm> I've been bad, and my SG has ranged from 1.020 to 1.024. I'm trying to get into the habit of 1.025 from now on. Nothing has died yet, however; usually, the swings occur when I add DI fresh water to top off once or twice a week.  <If there is this much evaporation, I would mark the water level on the tank and top off daily> The instructions for my DI unit said this was okay, and the SG would remain stable. However, I guess this is not true, and now I am premixing all water that goes into the tank. <Good idea> Secondly, would Feather Dusters do better in a bright, high flow area, or better anchored on the bottom in a slower flowing "cave"-type area with live rock overhanging?  <Depends on the species. Many are virtually dredged up from mucky under-the-dock areas... Other species are collected in clean, shallow reef areas. See our site (www.WetWebMedia.com) re these worms> I'm reading Tullock's book (But we carry yours at the store I work at, too! Do you have a suggested retail price for your book?) and he has a section on Worm Rock. <Mmm, maybe M/TFH have suggested retails... In the years of working with Microcosm we purposely set the suggested price points low and narrow at all levels of distribution to make our printed works affordable and re-sellable by independents ("Mom and Pop" stores). Think folks are still selling the paper-bound for about thirty US and the hardbound for ten, fifteen dollars more. Bob Fenner> Thanks, Ben

Specific Gravity Hello Mr. Fenner; <You actually reached Steven Pro. Anthony Calfo and I are helping out for the time being.> I have a silly question, and hope this is not a bother. <An unasked, unanswered question is silly.> I am a fairly new to the salt water trade, (6 months). I have read through the FAQ's on the WetWeb and could not find the answer. I also have read through your book. Both talk about raising and lowering SG, but does not tell exactly how to complete this task. My box Hydrometer broke, I bought a new one. I believe it is the six inch Hydrometer, suppose to keep your hands dry, any way I tested my SG this weekend and it was at 1.019. I need to raise the SG back up to 1.023 to 1.024. Can you please tell me how to accomplish this? Thank you for your time. Both your site and book has helped me immensely. <The easiest way to accomplish this is over the course of several water changes. Mix up some water to approximately 1.025 and do several small (~10%) water changes over the course of a week or longer. -Steven Pro> Sincerely, Lori

Emergency In The Reef Tank... Hello,  And thanks for taking my question. <That's why we're here! Scott F. at the helm tonight> A few days ago, after doing my normal weekly 10% water change I had a problem with salinity (.030) in my reef aquarium due to a faulty Hydrometer. <Yikes...been there before!> My salinity is now down to .023, where it should be? <Personally, I shoot for 1.025, but 1.021- 1.026 is acceptable> But my tank has taken a turn for the worse. I had to replace about 7 gallons of saltwater with fresh over 3 days. My water is now very cloudy and my fish appear to be struggling for oxygen. My PH level is low (7.6) but I'm using additives daily to correct that. Will this cloudiness eventually go away? Or did I replace too much water for my bio filter to handle? <Depends on the size of your tank...If you did damage your biofilter, you would want to avoid and more large water changes for a while, unless ammonia and/or nitrite levels are registering> Will I lose any livestock through this process? <Well, it depends on the levels of ammonia and nitrite, if present. Just take careful corrective actions as needed...nothing too radical. You could utilize chemical filtration media, such as activated carbon and/or PolyFilter, both of which excel at removing organics and potentially toxic substances from the water> Do you recommend using bacteria (Nitromax, cycle) in my case? <Well, if you're getting ammonia readings- it couldn't hurt to "re-energize" your system with some additional bacteria...Be decisive, but be level-headed, when taking corrective measures...Hopefully, things will work out okay with your tank! Good luck! Scott F> Charles Tizano

Thank God for your service (salinity rise) 1/20/03 I was wondering..... I had a spike in my salinity, for about a week, I was away and did not perform proper maintenance.  My salinity spiked to 1.027 in my reef and fish tank.  I was keeping it around 1.02 - 1.022 <I suspect that the drop back to 1.020-1.022 was more harmful than the "spike".  While you were away, the SG slowly rose due to evaporation.  When you lowered it, I suspect you did so fairly quickly.  Also, Natural Sea water is 1.025, and lower SG is more stressful on  corals than higher SG.  I always recommend 1.025 for a reef tank.> It seems that my Wes. Brain coral lost about a dime amount of tissue. Do you think it will grow back, hoping that is does not get a infection?  Thanks!<Probably not an infection, just a reaction to the stress of the salinity changes.  The tissue may take a very long time to recover or may be permanent, but the coral should be fine.  Also, just for accuracy sake, All corals known as Wellsophyllia and Trachyphyllia are all now considered Trachyphyllia.  HTH.  Adam>

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