FAQs on Marine Alkalinity Science

FAQs on Marine Alkalinity Science

Alkalinity is a measure of.... resistance to downward movement of pH... pH is simply a static value... a place... one can be high, the other low.. http://www.wetwebmedia.com/calcalkmar.htm

PhosBan Use and Alkalinity -- 12/20/10
Hello crew!
<<Hiya Gregg!>>
Thank you so much for providing such an invaluable service for us with all your information!
<<Is our pleasure to share>>
This question to you concerns my 50 gal reef tank's rapidly falling alkalinity. After reading many articles on your site and many of the FAQ's and articles regarding causes for alkalinity depletion in a reef tank, I saw one quick reference to the effect that use of PhosBan (Or would that be any ferric oxide hydroxide type of phosphate removers?) caused a depletion of alkalinity.
<<If true, it would apply to 'any' iron-based media I would think. But'¦ I don't recall anything to substantiate this claim>>
Does this really happen?
<<Not that I am aware'¦or at least, not to any great degree>>
Since there was only one brief mention out of all the other articles and questions, I would assume that it's not something that happens very often.
<<I don't think there has been any real 'science' performed to prove/disprove this, specifically. In fact, a quick search of the Net turns up claims that iron-based Phosphate media 'does not' deplete Alkalinity. But assuming for the sake of argument that it could, unless you are utilizing huge amounts of this media in relation to the water volume I don't think it is the source of any Alkalinity problems you may be having. In other words'¦I would look to 'other' causes re Alkalinity issues>>
Any info you could give about the chemistry of phosphate removers would be greatly appreciated. Is it possible that the PhosBan I use in a media bag that's layered together with Chemi-Pure, Poly-Filter, and Purigen in a power outside filter is either used up or is somehow competing with the other chemical filtration medias?
<<I don't think 'competing' is an issue. The use of differing methodologies (e.g. -- a DSB 'and' a vegetable refugium, or in your case, multiple filter media-types) only enhances water quality by bridging any 'gaps' in the performance of one methodology/media-type over another. But'¦these media will likely 'exhaust' at different rates -- it would be best to utilize them in media-specific reactors/filters, to be replenished as needed, for the differing media types>>
The tank water is currently tested weekly with a new (three month old) Salifert Phosphate test kit and the reading is consistently zero (or at least any color change is too faint to detect). The tank has been tested weekly since its startup 4 1/2 years ago and the Phosphate levels have tested out as essentially zero for the last three years. The tank receives 20-25% water changes weekly of Reef Crystals made up of RO/DI water that's been circulated and aerated for 12 to 24 hours before being mixed to a SG of 1.025 then aerated for 24 hours before being used. Despite the water changes, the tank's alkalinity falls by 1.0 meq of alkalinity weekly (tested with a Salifert KH/Alkalinity test kit), despite receiving daily doses of Seachem Reef Builder (1 tsp for a 50 gal tank). Is it possible that the main culprit is a high nutrient load in the tank, even though nitrites and nitrates test out at zero (The Seachem nitrite/nitrate test kit still tests OK whenever the reference sample supplied with it is used to see if the kit is still working).
<<Mmm, probably more an issue of the 'consumer' load in the tank'¦meaning that your salt mix and supplementation ratio are not sufficient to keep up with the tanks 'needs' re Alkaline materials. A simple increase in dosing is likely all that is needed here'¦especially so if this tank is heavily stocked>>
Is it possible that the tank's moderately heavy bioload,
<<Ah, a clue'¦>>
which includes too much red Cyanobacteria and other nuisance algae now, is extracting the nutrients faster than they can appear in the water column?
<<Almost assuredly this is so>>
The pH used to be steady at 8.2 for over three years until the bioload started getting heavier.
<<Indeed'¦and promoting an increase in acidifying molecules>>
Now it fluctuates from 7.9 in the morning to 8.2 in the afternoon.
<<Acceptable'¦in my opinion>>
The tank has pretty good circulation (about 2500 gph total with the power outside filter, sump pump, and two power heads all directed towards each other for some turbulence)
<<Do a Net search re 'Gyre' type flow for aquariums'¦seems much better/efficient than 'random turbulent' we are learning>>
so it's doubtful if there is a buildup of CO2 to erode the Alkalinity.
<<Not necessarily'¦ A high concentration of Carbon Dioxide in the house (due to being 'sealed up' for the winter, and especially so if using gas/propane fired heating) could contribute to higher CO2 loads in the tank water'¦even with a lot of 'flow'>>
Yet the alkalinity continues to fall at a rate that would be critically low in only a week or so if left unattended to.
<<1 meq/L of Alkalinity lost weekly is not exceptional in my experience, and should be easily adjusted with additional dosing (and cheaply, with simple Sodium Bicarbonate/Baking Soda)>>
Hopefully this short description of the system and some of its chemistry helps. I'll be happy to supply you with more info if you need it.
<<It really just sounds like your system has a bio-mineral demand that is higher than what is currently available. Perhaps your 'load' is such that the addition of a Kalkwasser or Calcium reactor is warranted. You could also swap out some 'old' live rock for 'new' live rock to boost bio-mineral content of the system. Or simply step-up dosing as suggested earlier>>
Thanks again for your help.
Gregg Voss
Buena Vista, Colorado
<<Happy to assist'¦ Eric Russell -- Columbia, SC>>

Alkalinity Falling As Calcium Remains High 10/9/10
<Hello Gene>
First, I did do some research before writing. I know you guys/gals encourage that - as you should.
<OK>
My dilemma: I'm running a CR <calcium reactor> and for a number of months my KH in my display
tank was running 9, 10 or even 11 on any given day. CA usually stays around 420. Lately, with the addition of a large monti - my KH has been dropping - now running about 8 an approaching 7. CA has remained steady - in fact today it was 480. I thought I had this CR dialed in - but perhaps not.
<The dKH in ocean water is generally 7-8dKH.>
I can dose Alk daily to raise the level in my tank, if needed. However (and this may be a problem of a different nature) the KH of the effluent coming from the CR is only about 14 - seems low to me. I use a controller for the CO2 and have the high side set at 6.67 and low at 6.48.
<Higher than needed calcium levels tend to precipitate buffers and is
likely what is happening in your system. High dKH and high calcium levels cannot chemically co-exist.
Whenever the dKH or alkalinity starts to rise, the calcium concentration will either go down or, you will have a very difficult time raising your calcium levels to the concentrations you want in your reef tank. Best to maintain the dKH at 7-8, and calcium at 400ppm.>
Looking forward to any advice you may have.
Thanks,
<You're welcome. James (Salty Dog)>
-gene
Re Alkalinity Falling As Calcium Remains High 10/9/10
<Hello Gene>
Thanks for your insight. Perhaps I was becoming concerned over something I shouldn't. I'll continue to monitor my parms -- and try avoid alarm if dKH stays within the 7-8 range.
A dKH range of 7-8 is perfectly acceptable and recommended for reef aquaria.
Have you read here? http://www.wetwebmedia.com/alkalinity.htm>
Regards,
<Ditto. James (Salty Dog)>
-gene
Re Alkalinity Falling As Calcium Remains High 10/9/10 - 10/10/10
<Hello Gene>
Wow -- thanks for that link, James!
<You're welcome.>
I really appreciate the advice you guys share knowing that you have no other motive than to help me succeed.
<You are correct, Gene. No other motive other than to help fellow aquarists succeed. The "crew" are all volunteers, including Mr. Fenner.
James (Salty Dog)>
-gene

Water Hardness/dKH And GH Confusion 4/21/10
Hello to all,
<Hello Jackie>
I have tried looking up the answer to my question on your site with no results.
My question is what does the effects of high GH have on a saltwater system?
<Is not something we test on marine systems. There are two types of hardness tests, GH (general hardness), and KH, or dKH (alkalinity) which is what we use/test for in our marine aquariums. GH or General hardness is primarily the measure of calcium and magnesium ions in the water. When a freshwater fish or plant is said to prefer hard or soft water, this is referring to GH. Carbonate hardness, or dKH is the measure of bicarbonate and carbonate ions in the water and is what we are concerned with.>
My tank is a 46g tank with fish and coral. 4 inch sand bed. The system is about 3 years old.
My readings are all good except the GH.
Cal. 400
Alk. 9 <9dKH>
pH. 7.9
Temp. 78
My GH is off the charts using the API test kit I've added over 50 drops and still no change in color.
<Not surprising.>
I use RO water and have tested this water using the same kit and this water changes after 1 drop.
<Yes, because it is 0 or close to 0 in hardness and is why you should buffer this water before adding the salt mix. In not doing so, the carbonates in the salt mix will/can be depleted.>
How do I get the GH down? I've done about 4 - 15 gallon water changes over the last 4 weeks with no change to my tank. Using Reef Crystals.
<YIKES, just forget using the GH kit, it is the alkalinity or dKH reading that we are concerned with.>
Some coral are doing just fine but other coral not so good. Most of my Zoas have closed and like dissolved. My Acans do not have good polyp extension.
Loss of general color in most coral. About six weeks ago I was killing Aiptasia using a Kalk mix and a large amount of this mix was added to the tank when the cup accidentally fell into my tank. I changed about half the water after this happened. My tank was fine before this accident. What can I do to get things back in balance.
<Your calcium, alkalinity, and pH (although a little low) are all fine. I believe reading here will help you appreciably in understanding this.
http://www.wetwebmedia.com/calcalkmar.htm
http://www.wetwebmedia.com/marphalk.htm>
Thank you.
<You're welcome. James (Salty Dog)>

Alkalinity Buffers 10/20/07 Crew, <Hi Scott> Can sodium bicarbonate be substituted for Sea-Chem's alkalinity buffer? They say that it is bi-carb based. <It can be, but I much prefer using Sea Chem Buffer as it is a blended product and not just carbonates. James (Salty Dog)> Scott

Re: Alkalinity Buffers 10/20/07 Hi James, <Hello Scotty> Thank you for the fast response. <You're welcome.> Along the same line of thought, I have read much on the topic of pH and buffering, and it has been written that in addition to testing pH and alkalinity, that one should also test acidity. My question is where do I find an acidity test kit I have tried several online stores and have even Googled the subject and cannot find an acidity test kit anywhere. All I can find is that most companies refer to pH as a measure of acidity. <pH is a measure of both acidity and alkalinity with pH 7.0 being neutral. Readings under 7.0 are considered acidic and readings over 7.0 are alkaline.> Confused, <Not any more, but do read here. http://www.wetwebmedia.com/marphalk.htm James (Salty Dog)> Scott

Re: Alkalinity Buffers 10/21/07 James, <Scott, and sorry for the Scotty.> Dare I correct you? 1) pH is NOT a measure of acidity and alkalinity, it is a measure of hydrogen ion concentration. <I realize that, just trying to explain in a easy to absorb format.> 2) Acidity is a measure of resistance (buffering capacity) to an upward change in pH, and 3) Alkalinity is a measure resistance (also buffering capacity) to a downward change in pH. 4) A /low pH reading is acidic, but not acidity, and 5) A high pH reading is alkaline, but not alkalinity. Read the link you referred me to if you are confused. Bob knows what he is talking about. <Yes, he does, which is why I referred you to the link.> 6) My name is Scott, not Scotty. <Again, sorry.> All I wanted to know is WHERE to find an acidity test kit and I finally found one at http://www.aquariumcity.net/Instruments/HI3813AlkAcid.htm <I've been in this hobby for 30+ years and have never heard of anyone wanting or using an acidity/alkalinity test kit. In my opinion, the standard pH and alkalinity test kits (of good quality) provide all the information that is necessary for my needs. James (Salty Dog)> Scott

Questions Regarding Alkalinity Hi there, I've searched the FAQs and the net for some quick answers to my questions, but haven't found what I was looking for. It seems that the responses only complicate the answer and confuse me more... So here are the questions Thanks in advance! 1. If my alkalinity is low can I use Kalkwasser to increase it? <Mmm, no... calcium hydroxide has no carbonate, bicarbonate content...> 2. Will Kalkwasser impact my pH? <Yes... hydroxides are strong bases...> 3. Is Kalkwasser's main purpose to 'maintain' KH and Ca at the current levels (not used to increase them)? <... please see WWM re...> 4. Assume that Alk is low and CA is low... should I use separate additives to reach desired levels... and then begin dripping Kalk? <You can...> 5. Dripping Kalk won't actually increase levels unless it drips faster than the evaporation rate correct? <What? No... almost all that evaporates is simply water... Please take your time here, learn what these concepts are, their interrelationships... not difficult with some application of your time, focus. See here: http://www.wetwebmedia.com/calcalkmar.htm and follow where the linked files at top lead you. Do you have a marine aquarium book? I'd look into Baensch Marine Atlas V.1... for simple, complete explanations of the basics of aquarium chemistry and physics... Bob Fenner>

Saltwater Chemistry 10/31/05 I've had fish in my 40 gallon tank for a month now (after a month of 30 lb of live rock cycling). Future plans call for soft corals. <Okay> For the past month, pH has been 8.2 -8.3, temp 75, nitrite 0, nitrate 0, specific gravity 1.023 - 1.024. Calcium started at 330 and I've slowly increased it to 450 with Kent liquid calcium. My Mardel test kit lists alkalinity at 240 (which is the middle of their buffer zone). How does this alkalinity scale relate to dKH? <Is one measure... carbonate hardness... generally principal component of total or general hardness... often described as alkalinity: http://www.peteducation.com/article.cfm?cls=0&cat=1968&articleid=2765 > Before finding your web site, I chose 1 1/2 inches of dolomite as a substrate. It is about 3mm diameter. I'm considering replacing it with 1 inch deep of aragonite. <Dolomites are compounds of calcium carbonate and magnesium carbonate... Aragonitic material is principally calcium carbonate... more soluble...> I thought I would leave a couple inches of the dolomite around the live rock (whose foot print is about 40% of the tank floor) to avoid major stirrings of the tank. Is this a practical move with fish already in the tank? <Mmm, yes> Does algae grow on aragonite more or less than dolomite? <Less in most circumstances> I've read "Conscientious" a few times and have "Reef Invertebrates" (Calfo & Fenner) and "Aquarium Corals" (Borneman) on my Christmas list. <Good books. Bob Fenner>

Restoring Alkalinity 2/17/04 Alkalinity tested way too low at 5dKh. We had only been using Kent concentrated liq. Ca once a week. Ca is at 420; Ph 8.0-8.2; other parameters ok except nitrates stay around 10ppm. <Alkalinity is THE most under-appreciated, misunderstood and commonly mismanaged parameters in marine aquaria. Many, many aquarists maintain Ca, but aren't aware of the need to maintain Alkalinity in a balanced fashion.> Tank is 220g w/200# LR; 15 fish (30 in.) 12 moving inverts & 12 mushrooms & corals (not counting 100s of hermits & snails). Lighting: 5x160w VHO; 2 VHO Actinic Whites 160w run 8 hrs/day. Skimmer is MPS 450 by Aqua Clear. 4 Maxi Jet powerheads @295gph. <All sounds good, but don't by into that old rule of thumb of inches of fish per gallon! Compare for arguments sake, the following: Twelve 1" green Chromis to one 12" Emperor Angel. The angel has probably 100x the body mass of all of the Chromis combined! With an average size of a 2" fish, you are probably OK, but do be attentive as the grow. Heavy fish loads will make it harder to keep nitrate down and alk up.> Yesterday bought Kent Tech CB parts A&B, and used B only at rate recommended on bottle in a.m. Only raised to 6dKh. My question is how often can I add this buffer to correct problem. Should it also be added to R/O top off water? <It could take A LOT of this product to restore your alkalinity. It will be perfectly safe to raise your Alk by 1 dKH per day. Once your calcium and alkalinity are both in an acceptable range, start using both components to maintain both parameters.> 55g sump looks pretty cruddy, too; as well as column skimmer is in. How do I clean it? This project is getting too scientific for my brain! Please help. Thank you, Kathy Harper <Cleaning a sump can be tricky. You can run a long siphon hose down some stairs to a lower floor of your house, or use a wet/dry vacuum. Skimmers should be removed, disassembled and scrubbed. Best regards! Adam>

Re: Restoring Alkalinity 2/22/04 Adam: Thank u for your prompt assistance. Is it ok to treat daily to restore alkalinity? <Glad to! It is not only OK, but in fact ideal to make small adjustments on a daily basis, rather than larger ones less frequently. Best Regards. Adam>

Alkalinity Hi Crew, Many thanks for all the work y'all do in supporting the hobby. I've only been in the game for 2 years now, but I constantly refer to you and have found your book and article recommendations tremendous--enough flattery for now. <I'll say!> My 150 budding reef tank has been very stable for 2 years with slow addition of a few LPS's. Good skimmer and flow with 10% water changes bi-weekly. About 150 lb. of nicely encrusted Fiji with very light fish load and about 2" of aragonite. Only real change of late is to add 2x250 HQI halides to the 4x96 PC's (now all actinic). This was done about 6 weeks ago with a view toward more corals to come. Gradually increasing MH photoperiod to current level of 6 hrs. per day while trying to let algae growth cycle and stabilize with each incremental increase in photoperiod. <Sounds good> My alkalinity has been stable above 9 dKH while Ca has stayed above 400 and pH 8.3 ( I dose with Tech 2 part Calcium buffer at the same level for over 9 months now). My problem seems like a total newbie question, but the more I read, the less certain I become of the best solution. Within the past 3 weeks I've found my dKH falling to current 7.7 while Calcium ranges 360-410 and pH still 8.2 or better. Other observations: Some coralline algae (very small percentage of total) near top of tank has died and bleached. My sand sifting starfish has started spending much more time on top of the sand bed and is rarely ever concealed. Emerald crabs have turned much lighter bleached color from previous green and become more diurnal. Is any of this related? What role is the MH photoperiod playing, and most importantly, how can I reverse the decline in alkalinity? Thanks so much in advance for your assistance. <Good descriptions! All tied to your new lighting... driving photosynthesis... the biomineralizing life and reductive effects of respiration in a closed system exhausting the alkaline reserve... Let's cut to the proverbial chase: You can either restore previous levels with addition of "two part" supplements (alkaline earth... calcium, magnesium... AND alkaline reserve... carbonates, bicarbonates...) OR switch to a "calcium reactor" of sorts... or... Bob Fenner>

Re: alkalinity Thanks for the prompt reply and affirmation of what I suspected (hoped) was the problem. I've been looking at calcium reactor as next on wish list... the only question is how urgent or dangerous is this dKH decline and how long before I need to make the addition? <Mmm, read over www.WetWebMedia.com here... as usual, too much to simply answer in a brief response... that needs to lead to next logical interrogatories... you want to fix this now, someway> In the meantime I suppose I can increase my dosage of Kent's 2-part Calcium buffer to hold the line until reactor installation--correct? <Ah, yes.... I should (as usual) read ahead> Thanks again for everything-I've been reading your info on Ca reactors and will continue to do so. <Real good. Bob Fenner>

Soda Ash Hi Crew, <Terry> Just a quick question. I have three reef tanks and live near a soda ash mine. I use the soda ash in the swimming pool to adjust the alkalinity. Will this work in place of the SeaChem Reef Builder that I have been using to adjust alkalinity in the reef tanks? I can buy a 25 lb. bag for about the same price as a jar of the SeaChem. Thanks, and keep up the good work, you all are great!! Terry <Mmm, well soda ash is simply sodium bicarbonate... baking soda aka... so, you could just buy "Arm & Hammer" instead if this is all you wanted... You will find that the commercial products contain at least a carbonate and an anti-caking additive... At any length, if it were me, my system I would NOT use the soda ash from the mine, for fear of contamination... but would use the processed food grade if all you want is to add bicarbonate... you will find by experimentation that this material will not elevate your pH more than about 7.8... Bob Fenner>

Alkalinity too high? 3/16/05 Hi, I'm new at marine aquariums and am having some trouble. <no worries... its a wonderful learning curve> I bought a test kit and have been testing for 2 weeks, now. It tests pH, carbonate hardness, NO2, and NO3. I also measure temp., spg, and salinity. I thought everything was great, but I couldn't figure out the carbonate hardness or alkalinity. <tough to sum up in a brief e-mail, but the gist of it is total hardness vs. carbonate hardness for starters. If your kit only tests for the latter, no biggie... it is indeed most of the total hardness in seawater> My brain just couldn't understand for some reason. Finally, it clicked and I've discovered it's way high! However you figure it, these are what I get: 250ppm, or 5.0 meq/l, or 14 degrees carbonate hardness. That's high, right? <it is high... not too severely. 12 dKH is high enough as long as your Calcium is a bit flat (under 400 ppm, e.g.)> How can I fix this? <a large water change and some time... no worries> We used potassium softened tap water originally, <yikes!> but then used distilled water and mixed it with Instant Ocean as directed and did a partial water change. <hmmm... you may need to buffer the distilled water slightly. Yet with distilled water, I cannot see how your ALK got so high? Have you added SeaBuffer at some point in time? That would be the logical explanation (overdosing SeaBuffer)> My pH is 8, salinity is 30, and spg is 1.023, temp. holding at 77. We also set up a small quarantine tank with distilled water and Instant Ocean and came up with the same readings. I don't think it's my water then. In my main tank, a 29 gallon, I am using the Skilter filter, along with 2 airstones. We have a 5 lb. live rock and used live sand/crushed coral as substrate. We do have 2 clown fish, a tang, and 2 small hermit crabs. I had 2 other clowns first, but 1 lasted 7 days, then the second died after 11 days. I don't want to lose any more! Can you help? <please also read the article "Understanding Calcium and Alkalinity". Do a search for this article on our home page at wetwebmedia.com by using the Google search tool there. Kindly, Anthony>

Understanding Alkalinity Hi again, <Hi there! Scott F. back with you today!> Finally, my tank got cycled last week. I added a flower pot, frags of candy and a green button polyp. The LFS told me to add some Alkalinity Buffer. What does this do? and If I need it, which brand shall I get? Thank you, Felix <Well, Felix- I'm not sure why the dealer recommended that you get the buffer. If he or she tested your water and determined a need, then I can understand. It all boils down to basics, I guess. Alkalinity is a measurement of the buffering ability (capacity) of your system. Alkalinity is sometimes depleted from systems by improper dosing of calcium supplements. Calcium supplementation without the appropriate carbonate added as well can knock your alkalinity way out of whack! My advise is twofold: First, get an alkalinity test kit. Second: Get yourself a nice tall glass of Thai Iced Tea, some popcorn, and a little quality time on WWM reading over the alkalinity FAQs. That will really help you get a grasp on the calcium alkalinity dynamic, and an understanding of pH in your system. It's worth the effort to learn! Good luck, and have fun! Regards, Scott F>

First time Kalkwasser/Calcium User - 8/13/03 Hi, <cheers> I have a 180 gallon tank and my coral is changing colours quite significantly. <Many possible reasons... excess nitrate if darkening in color, insufficient nitrate if paling, too much or mot enough UV... dirty lamps or lenses, aging bulbs, lack of weekly/monthly carbon to maintain crystal clarity to water, etc> I am trying to research the benefits of Kalkwasser versus Calcium but it's getting kind of confusing. <Kalkwasser is calcium mate... are you confusing it with carbonates/buffer?> I understand that Kalkwasser is literally calcium hydroxide, so is this the same as "calcium only" products (such as Reef Success Calk, Kent Marine Turbo Calcium Dry, assorted calcium concentrates, etc)? <nope... Kalkwasser is better (many more benefits to it... read about them in our Kalkwasser FAQs in the archives of wetwebmedia.com). The latter products are generally just calcium chloride which is only a temporary supplement for calcium (can cause long term problems if used regularly)> If so, that makes this a lot easier, but if NOT, then what do I do? <do read my article "Understanding Calcium and Alkalinity" in the archives> If it matters, the coral types I have are colt coral and anemone. <please also read about eh dangers of mixing sessile corals with motile anemones. Its a recipe for disaster in the long run. Do keep anemones separate> Your site is great to answer questions that I might have after I get going, but I just need a little help getting started. Any suggestions? Thanks, Raj <all good my friend... begin here and read the links at the top of the page and beyond: http://www.wetwebmedia.com/calcalkmar.htm best regards, Anthony>

High Alkalinity & Calcium Hello, My alkalinity and calcium seem quite high for my FOWLR tank, yet my pH stays rather low. Alkalinity is 5 meq/L, calcium is 450, and pH ranges from 8.0 to 8.2. <These are all fine.> Are these numbers anything to be concerned about? <No, not really. As long as they all stay consistent.> What is the best way to get my pH up without getting my alkalinity and calcium any higher? <Aggressive protein skimming to remove dissolved organics that affect pH.> I've added quite a bit of Macroalgae and that has helped somewhat. <Yes, helps in several ways; taking up the dissolved organics mentioned above and also consuming CO2 during the daytime.> Thanks for your input. Chip <You are welcome. -Steven Pro>

High Alkalinity & Calcium III Steven, Thanks again for the reply. Okay, so how do I increase the pH without raising the alkalinity and calcium? <Water changes, protein skimming, activated carbon, etc.> And is the 8.4 you suggested the LOWEST the pH should go? -Chip <About average, anywhere between 8.2-8.6 depending on time of day, supplements used, lighting, photosynthetic animals, etc. -Steven Pro>

Re: High Alkalinity & Calcium Steven, Thanks for the reply. As a follow-up, my AquaC skimmer (only 4 weeks old) occasionally goes on 'strike' for two days or more after a water change and after I've had my hands in the tank. Is it normal for it to go this long without skimming? <Yes, it is disrupted briefly.> It eventually resumes, but it just seems to take a while. Also, I will be putting a raccoon butterfly in this tank. I've read on WWM that they like higher pH and salinity. My salinity is currently 1.023. Should I increase it for the butterfly? Is my pH (8.0-8.2) okay? <I would increase both to natural seawater conditions; 1.025 and 8.4> Thanks again, Chip <You are welcome. -Steven Pro>

Help? Question Hi, I have an question to ask you if you don't mind. I have a 55 G reef tank that has been set up now for about a year. Everything is testing fine but my alk. is testing at 5.00 mEq/l and my ph is 8.0 How can my ph not be higher than this value if my alkalinity is high? <Easily... these measures are not directly positively correlated. Alkalinity is a measure of.... resistance to downward movement of pH... pH is simply a static value... a place... one can be high, the other low...> I'm trying to get my ph to a stable 8.2. I did accomplish this for a time with Proper PH 8.2 buffer but it dropped back to 8.0. My calcium is about 460. <Ah! Likely your focus on driving the biomineral content of your water is your real nemesis here... self-caused. Please read through the various sections on pH, alkalinity, calcium... posted on our site: WetWebMedia.com and accompanying FAQs pages> What is causing my ph to drop if my alk. levels are high? Please help... thanks <You can only help yourself... give up your fixation on any one given value... the linearity of your thinking is the source of the "trouble" here. Bob Fenner.>

ALK, Calcium Greetings! <Cheers, Anthony Calfo in your service> I have what seems to be a fairly successful reef which has a TON of money into it and all life in there seems to be well. I have an open brain, magnificent anemone, frogspawn, green star polyp, and about 10" in fish. Here goes: 125 gallon, RO/DI water, 6" 175w MH/VHO Canopy, 180lbs. live rock, wet/dry, carbon, heater, chiller, Aquacontroller II, Aqua-c EV-120. Water parameters: 80 degrees, 1.023 SG, Ammonia =0, Nitrites=0, Nitrates=<2, Cal 380-400, Alk 2.5 meq/l, PH 2.3 at night - 2.45 during the day, <The alkalinity is too low and the pH is clearly a typo...resend please> My dosing schedule is: Monday & Tuesday dose 2.5 gallons/day of top off dosed with Seachem Reef Plus, Advantage Calcium and Reef Calcium, Tuesday and Wednesday - Reef Builder (raises carbonate alkalinity) Thursday and Friday, just advantage calcium, Saturday and Sunday, Reef Builder. Obviously the Alk is low and so is the SG. I am not dosing Kalkwasser. <I strongly recommend Kalkwasser> What do you recommend to raise alk? <common Seabuffer if using Kalkwasser or two part liquid supplements if using neither (like B-Ionic brand or Sea Balance)> Just keep doing what I am doing? <heck no> Let me know your thoughts on just using the liquid and powder calcium chloride. <calcium chloride should only be used alone in emergencies... it is plagued with problems for daily use in the long run> Should I supplement some Kalkwasser in the schedule? <daily for optimum coral growth and saponification (improving skimmer performance)> If so, how often. Thanks! Adam <best regards, Anthony >

ALK, Calcium II Thanks for the reply Anthony! <very welcome> Follow up question for you or two. 1) Why is daily use of Calcium Chloride a problem? <accumulated chloride ions can skew the alkalinity/Ca dynamic.. making it hard to maintain alkalinity> 2) So, you would dose Kalkwasser daily and how often would you use a buffer? Is this an alkalinity buffer? <not a buffer directly, but reduces the amount of buffer needed in a system to maintain Alk while increasing Ca> 3) Do you see a problem with biweekly dosing of Reef Plus ( Vitamins and minerals for corals)? Actually they (Seachem) recommends just dumping 6 capfuls (for my 125) into the sump. <experimentally it sounds fine... I like regular water changes as much or better for this purpose. Anthony>

Alkalinity Pool- kH question Hi! By-the-way, you're a great crew!!! <Thanks kindly> I'm going to ask you one question: Month ago I was dripping Kalk - it did great job > my kH rinse from 7 to 10 {dKh} <very good to hear... as hoped/expected> Then I stopped for a week to see what will happen. kH rose to 8 so I started to drip again {1 week ago}... Why is my kH is still 7 and didn't move???? I'm doing everything like then but it don't 'want' to move... What cause that? My Ca was 410 all the time so I'm not worrying about it. <my apologies, but its not clear to me exactly what your question is my friend. Are you comparing/testing for carbonate and/vs. general hardness? If so... it is possible to have a slight discrepancy between the two although they are usually close/similar. Perhaps it is best to determine what your natural daily drop/demand is for these parameters... then test to see what the rate of delivery your present drip dose delivers is. You will then have an indication if you are dosing enough. Best regards, Anthony kH question I'll clear my question: Why my kH isn't rinsing even if I drip Kalkwasser? <Ahhh... yes. Understood, my friend. The reason is very simple... Kalkwasser only indirectly supports (although it usually does it very well) carbonate hardness by providing caustic (high pH) hydroxyl molecules which neutralize acids in the aquarium that would otherwise "chew up" your pool of carbonates (kH). But Kalkwasser does not actually deliver carbonates... remember it is a "calcium" supplement. For extra carbonates, you need to use a buffer product (containing sodium carbonate/bicarbonate). Aquarists typically dose buffer by day, and Kalkwasser by night. IN systems with a nice deep bed of fine aragonite sand, you may not need much or any buffer, and Kalkwasser alone will support both Ca and ALK. But in your case... it sounds like you may need to be adding a little bit of sea buffer powder too> I'm doing everything like before to push but it don't want to move... Best regards and happy weekend Peter <no worries... easily misunderstood... our tanks need calcium + carbonates to make calcium carbonate structures. Both must be kept in good supply and stable, else you will not realize growth. Best regards, Anthony> Alkalinity What should be the range of alkalinity in a salt water tank mine is 38 gallons <target 12 dKH for general care and higher if reefkeeping. Anthony>

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