Using Kalkwasser to Raise pH – 06/05/08
Hi there,
<<Hello>>
Thanks for your time reading this.
<<Certainly>>
I have an AquaC RX-1 calcium reactor using Knop Korallith media. My 75 gallon tank is a mix of sps, and some soft corals. My house is sealed well and when using ac in summer or heater in winter I can’t open windows cost effectively. I know through testing I have high carbon dioxide levels when the windows are closed and my family is all home breathing. My only concern is my pH. Using calibrated Pinpoint probe it reads 7.9 during day and sometimes 7.8 to as low as 7.68 in mornings after 24 hours of the house being sealed.
<<Mmm, I see…>>
I’m a perfectionist with my reef and want 8.1 to 8.3 like I had before adding my calcium reactor.
<<Agreed…better to maintain these higher values overall>>
My calcium is always at 400ppm and Alk is always at 10dKH. Is topping off the evaporated water with Kalkwasser just to raise pH a bad idea?
<<Not if done carefully/slowly…and monitored closely. I have used Kalkwasser in conjunction with a Calcium reactor for years. And while I don’t consider this ideal as doing so usually results in a see-saw effect on pH, as well as requiring careful monitoring and maintenance to ensure against depletion of Magnesium ions…there is certainly benefit for those systems requiring either more Calcium than their reactors can provide (not the issue here it seems) or with helping to boost pH by consuming those elements which suppress the available buffers (e.g. – excess free Carbon Dioxide (which does seem to be your issue)>>
I don’t really need to raise calcium or alkalinity and the only way I can think to raise pH would be with this method.
<<Maybe so…but your Calcium and Alkalinity levels are already nearing the high end, you will need to proceed with caution>>
I’ve tried running skimmer air intake line outside and using nighttime lighting on the refugium but nothing seems to work to raise pH to acceptable levels without the windows being open.
<<It would appear your issue is certainly related to excess CO2>>
I also installed a second reaction chamber filled with Korallith to try to raise effluent pH.
<<A good move>>
My concern is the Kalk...will it just precipitate calcium and alkalinity out of my water, clouding it and cause more trouble than good?
<<I think a “very slow” drip (in to the refugium), monitored frequently, is of little risk and worth a try>>
Or with such a high amount of dissolved CO2 in the water will it simply all bind with the dissolved CO2 and form calcium bicarbonate harmlessly while raising the pH?
<<Obviously this is the desired result…and is what I think should happen as long as the Kalkwasser is not added too quickly>>
What do you think I should do to solve my pH issues?
<<Give a Kalkwasser drip a try. Proceed slowly… monitor your pH/Calcium/Alkalinity levels often, stopping the drip if any problems manifest…and don’t expect results overnight, give the method some time to work. EricR>>

Bringing Down The Phosphate…Understanding Elevated-pH Phosphate Removal Mechanisms – 03/13/08
Hello, Crew.
<<Greetings, Todd>>
While trying to run down the source of my elevated phosphate in my 225 gal fish and invertebrate system, I would like to bring it down fairly quickly (a band-aid only, I know).
<<Indeed>>
I have read about the method of raising the pH overnight to precipitate the phosphate in the Wet Web Media pages, but I'm too big of a weenie to do this.
<<I see… But Todd, you don’t want to raise the pH for the entire display to the level required to “precipitate” Phosphate, as that would certainly be deadly to the system. Instead, you would “slowly” elevate and maintain the pH at 8.4 to maximize the “binding” of Phosphate to the Aragonite surfaces in your tank. This can be done with Kalkwasser additions, which will also “precipitate” Phosphate from the water column in the area of locally high pH where the Kalkwasser/ Limewater enter the system. The “binding” of Phosphate to the Aragonite surfaces is arguably problematic as there is some speculation that if the Calcite crystals stop growing there is potential for releasing Phosphate. The “precipitation” of Phosphate in the water column may be less problematic since the Phosphate might become coated with organics and be removed by the skimmer. The short-term advantages here for Phosphate removal seem obvious…the long-term effects could be debated, in my opinion. “Complete removal” of Phosphate from the system is likely the best answer…as in the use of macroalgae in a refugium (periodically “pruned” and discarded), the use of reactor with an iron-based binding agent, etc.>>
Can't such a rapid pH change hurt my fish or inverts?
<<Rapid changes to “anything” in your system can be deleterious, yes>>
I also ran across a Korallin product (P04 minus) which apparently complexes the phosphate to something that is easily skimmed (I have a pretty aggressive skimmer running), thereby "exporting" the phosphate through the skimmer. Any experience with this method?
<<Not personally, but I do have a friend here in town who owns an LFS/Service business who swears by this stuff. But then, he swears by “everything” he sells [grin]>>
I worry about what desirable ions it might bind and remove via my skimmer.
<<Indeed…and maybe not so much removal by the skimmer as just outright precipitation from the water column. The literature seems to indicate the product may cloud the water…and to keep an eye on KH to prevent a dangerous drop… Warning flags? Sure… But then this product is likely no more dangerous to your system than Kalkwasser. Give it a try if you wish. But just like anything else, use good sense/judgment…and proceed with caution>>
Thanks in advance for your help and thanks for the great web page!
Todd in Montana
<<Happy to share. EricR in SC>>

Kalk dosing - 11/26/07
<Hello Jeff,>
I have a sort of quick chemistry question.<Ha! Quick?> I did get a degree in chemistry as an undergrad, but without use, pretty much all knowledge has disappeared. I have been dosing Kalk by trying to get stable readings on my kH and Ca tests and have used a separate 2 part mix to fine tune the kH/Ca balance. My current readings are kH 11.2 and Ca 370.<KH above 10 will drop calcium below 400ppm>
This system doesn't really address pH maintenance unfortunately, and that parameter has had some fluctuation (7.9-8.2).<The pH will fluctuate naturally as the KH and Calcium levels change. It will also bounce a little (few points) with light levels and photoperiods.>
Basically, my understanding is that the kH is a measure of the buffering capacity of the water, i.e. the ability to resist change in pH.<true>
Kalkwasser is a solution of CaOH that both maintains the kH and the Ca in roughly the same proportion.<Yes and no. Kalkwasser, also known as Calcium Hydroxide will raise the pH significantly(over9.0) and boost calcium levels. It's main purpose is to supplement RO/DI water back to a buffered solution and to add calcium daily with make up water from evaporation. It will not be a reliable buffer for pH and calcium levels alone.>
Consumption of buffering material by stony corals and the buildup of C02 and organic acids all contribute to decreased pH. I have very good aeration, and have tested the pH with vigorous aeration and see no difference, so retained CO2 does not appear to be impacting my system pH significantly. Any build up in organic wastes will decrease the pH and consume the buffering capacity, proportionately dropping the kH, true?<Yes>
Based on all of these postulations, I've come up with the following hypothesis: A drop in pH is a ultimately a direct reflection of lost buffering capacity. Measurement of pH is thus an adequate parameter for assessing consumption of kH, whether by coral consumption or binding to organic acids and being skimmed off.<NO. pH is far too unstable in reef aquaria as so many outside forces affect it in a 24 hour period. For example, lighting with Metal Halides can increase pH levels at the end of a 10-12 hour photoperiod, yet the lack of light will lower the pH at the opposite end of the photoperiod. Bio-load and fish activity, feedings, etc. will all have small affects on pH(1-2 points like 8.2-8.0)>
If this is true, then Kalk dosing could be automated to maintain a stable pH. I haven't really heard of anyone doing this, so I think one or all of my premises are off base. I figure there are more factors at play. Setting the Kalk reactor to turn on when pH drops below 8.2 probably bears significant risk of dangerously increasing kH and causing supersaturation and precipitation or "white-out". Why this would be true, I don't know and would appreciate your input.<If automated, the chance of precipitation would be much higher as you stated. The reason is there would be a build up of buffer over time that the system would not be able to balance out. Also, the higher buffer levels would lower the Calcium levels too low. Let's say the pH reached 8.4 .How would you remove buffer to get the pH back to 8.2? There in lies the problem. It only buffers automatically up the scale.
In the end, Calcium and Alkalinity levels are paramount and pH is really not as important. (outside of some strange extremes). So, if Calcium is maintained at 400-430ppm and Alkalinity levels are between 8-10 KH or 3-4meq/l then the pH will fall between 7.9-8.3 naturally thru out the day.>
Here are some more articles to explain further...
http://www.wetwebmedia.com/calcalkmar.htm
http://advancedaquarist.com/issues/may2002/chem.htm
http://advancedaquarist.com/issues/feb2002/chemistry.htm
http://www.reefs.org/library/talklog/d_warren_090797.html
Enjoy!>
Thanks so much for your help,
Jeff
<no Problem, Rich...aka...Mr. Firemouth

Kalk drip and other questions 6/6/07
First of all, thanks for keeping such a great site on the web. I have been reading for months now and finally am starting to understand more about this hobby.
<Ah, good>
I still do have some questions though about top-off and dosing.
<Okay>
I have a 29 gal reef with a good amount of live rock 35-40 lbs and a good 2 inch sand layer. I just upgraded to a CPR overflow, a Euro-reef skimmer and a RO/DI unit.
<Good improvements!>
I am using a 10 gal aquarium as a sump which has about 7.5 gallons in it making for a total of 27-30 gallons total water. I evaporate about a ½ gallon a day (maybe more) and want to get a good understanding on daily top off water regimes, supplements and additions.
Ph. 8.0, Alk 8-9 Calcium 340-380, Magnesium 1050. As you can see all of these are really low except maybe the alk.
Here are the questions I am hoping to get clarification on. 
1.) How much can I raise magnesium in one day and what to use.
<For the little difference you have to make up, you can "jump" this up in a day or two... with Magnesium Chloride or Magnesium Sulfate>
Right now I have some SeaChem magnesium and it looks likes I am going to use all I got (small bottle) and are there other ways to do this.
2.) I want to understand Kalkwasser and buffer. It seems that both of these should be used for good results for the Kalk provides the calcium and buffer provides CaCO3 adjusting pH and alk, right.
<Mmm, roughly, yes... the Kalk alone does not provide alkaline reserve>
If I was to lose a ½ gal of water a day can I pour a ½ gal of made settled Kalkwasser into the sump or does it have to be dripped?
<You can experiment here... many types of set-ups (particularly large, stable...) can take just the dumping in/slurry methodologies, but in such a small volume, dripping is vastly preferred, safer>
And can I add buffer at the same time or should it be on opposite days?
<Best to do on different occasions/times>
As far as the Kalk goes what is a good amount per gallon?
<As low a concentration as needed in this technique... That is, if you only need/want a "teaspoon" let's say, to dissolve this in the total volume of however much water you're going to/want to add>
3.) Should Kalk and buffer be added every day?
<Only if necessary, and not at the same time>
I have a hard time understanding if supplements should be added to you get the numbers you want and then backed off or if this is an everyday thing.
<Mmm, yes... a good lesson for "western" thinkers... with "linear" conditioning... You can consider that you're always striving, aiming for some relative place... never there, but approaching... Healthy>
4.) When I do a water change (every 10 days on average at 10%) should I
match the water with what I want in the tank?
<Mmm, likely "overshoot" with what you want in the tank...>
I wanted to know about Cacl2 and buffer for this.
<Mmm, I would not get involved with Calcium Chloride. Reasons, rationale posted on WWM>
Thanks for all your help and I look forward to your response.
Will
<Good questions Will... keep that curious mind, learning, sharing... with a dose of cynicism, and you'll do fine. Bob Fenner>

Kalkwasser, pH, dKH...And the Need for Understanding - 04/14/07
Hi there,
<<Hello>>
I'm quite new to this hobby and have been reading your fantastic site since I started 7 months ago, having taken over from my teenage son who lost interest when he couldn't stop algae problems.
<<I see...well then, welcome to the hobby>>
I have a 20 gall (UK) reef tank (I know, too small, working on getting a bigger one) with 3" LS substrate and 25lb of LR with lots of lovely coralline.  A few soft corals that are all doing well and some acropora that I think are ok.  Parameters temp
80F, SG 1.025, Ammonia 0, Nitrite 0, Nitrate 12, phosphate 0.015, Ca was 280, Alk was 2.8, but pH 7.7 at night and 8.0 just before lights out (2 actinics and 150w MH in an over tank unit). 15% weekly water changes using Instant Ocean and RO water.
<<Hmm...nitrate is a bit higher than I like (would prefer 3-5 ppm), and I'm surprised at the Ca reading considering the weekly 15% water changes...you should probably verify the accuracy of this test kit>>
I was advised by my coral supplier to use Kalkwasser which reading your site you would seem to endorse, so I bought a peristaltic dosing pump and some Seachem Kalk to use with my RO top up water.
<<Indeed many here do endorse the use of Kalkwasser, myself included.  But it is not to be used without caution/some understanding of the product as it can be easily abused...especially on a small system like yours>>
I lose about 1.5 litres a day to evaporation so last night I set up the drip system to add my Kalk over about 7 hours.  I now have a pH of 8.3 which is great (but if previous form with pH buffering continues it will fall back to 7.9) but a KH of 13!
<<Hmm...>>
Have I done something wrong?
<<Don't know...  Kalkwasser is intended as a calcium supplement primarily...and when used properly, has added dividends of boosting pH and helping to support alkalinity (mainly through the "burn-off" of organic/acidic molecules).  Though at the high end of the scale (assuming this reading is dKH, since you don't specify), this KH reading is not "bad," but it is important to know here what the calcium reading is as well, the two should always be considered together>>
Should I add more Kalk every 1-2 days as top up?
<<Mmm, no...in fact I suggest you stop with the Kalkwasser altogether until you gain a better understanding of the chemistry involved/marine water chemistry as a whole.  Please start reading here and among the links in blue at the top of the pages:  http://www.wetwebmedia.com/calcalkmar.htm  >>
I have plenty of water movement, a venturi driven skimmer which should help water aeration), or have I got a CO2 problem?
<<...?  Why would you think you have a CO2 problem?>>
All corals and fish look healthy except for a Pacific Green Button Polyp which has been fine for 6 months but now buttons won't open properly and are rather brown instead of green.
<<And likely an unrelated issue>>
Sorry for the length of this email and all the questions but you guys are the best so I'll do whatever you say.
<<Honestly mate, considering the size of the system and the stock list involved, you really DON'T NEED TO DOSE KALKWASSER.  As already eluded, the 15% weekly water changes are the best vehicle for keeping/are more than enough to keep your water chemistry "balanced" in this small tank.  If test results seem to be indicating otherwise I would first suspect the efficacy of the test kits.  Fresh kits might be needed...or "better" kits might be needed.  I suggest kits from Salifert or Seachem as good quality "middle of the road" kits...or you can go "high-end" with LaMotte and Hach, maybe even Merck.  If the test kits prove good, then look to your salt mix/mixing protocol (start reading here and beyond:  http://www.wetwebmedia.com/seah2omixing.htm)...perhaps even trying a different batch/lot/bucket of salt mix.  Bottom line here is you don't need Kalkwasser additions with this tank.  I do encourage you to read up on its use and the dynamics involved and make your own informed decisions...but for now, the frequent water changes with a properly prepared quality synthetic mix will save you much headache/possible disaster.  And no worries re the length of your query...the more info we have the better we can help>>
Roger in the UK
<<Cheers, EricR...who lived/kept an 80g reef in Ipswich for 3.5 years back in the late eighties/early nineties>>

Supplements: absolutes in a relative world
Bob,
I got the clowns, lights and the live rock and live sand on Saturday and was up until 3 AM getting everything put in place.
<Yowzah, late night>
Now I have some live rock with a fair amount of macro algae growing near the top of the tank. I have not installed the new lights yet (two Hamilton 55w
bulbs, one is sun-light the other actinic blue) because I need to rig them somehow...
<Yes>
The guy I bought the stuff from seems pretty knowledgeable and he sent me the message below that emphasizes the need for calcium/Kalkwasser to promote the growth of the macro algae. Do you agree with this?
"I must emphasize, especially now that I can't be accused of peddling my Kalkwasser, that is paramount that you add calcium supplementation to
the tank with the rock, without it the macro alga will stop thriving as it is the calcareous type, and the micro inverts present in the rock (a
few of which I showed you) will also die off. The rock will not produce any more ongoing life either. Piddling micro life, yes. Healthy micro
fauna populations, no. You need to add either balanced ionic solutions or add calcium via limewater (Kalkwasser) additions."
<Yes, I absolutely agree with the need to supply biomineral and alkaline reserve. Not necessarily via Kalkwasser though. Bob Fenner>
Thanks, John

Clarification: Baking Soda and Kalkwasser
Bob (or whoever is on-line today),
<The aquarist formerly known as Anthony Calfo... you may now call me Antoine>
I am a bit confused about a couple of things and need some clarification. I have been using tap water, filling the bucket, adding dechlorinator/dechloraminator, mixing my salt, and placing (and circulating) in a 10 gal aquarium for a week until my water change. 
<that would be about 6 days longer than necessary for the way you've chosen to make seawater>
I do this all at the same time, but today on the Q&A page I see someone was getting advice to store and aerate the water for 12-24 hrs before adding anything to it.
<yes...IF using purified water (like R/O or DI) which has been demineralized and is temporarily acidic (from carbonic acid)>
I don't recall this advice in your book The Conscientious Marine Aquarist,
<mostly a reef-keeping thing...not as much purified water use among fishkeepers who can usually get away with tap water like yourself>
only to mix up the seawater and store it for several days. Should I continue as I have been? And does aerate mean leave the bucket with the lid off, or will stirring it up once a day do the trick?
<after dechlorinating your tap water...circulating the salt mix with a water pump or aerator for 12-24 hours for the dissolution of salt mix and the saturation of O2 from the atmosphere will be fine... relax. If you are not having difficulties such as nuisance algae that could be attributed to source water, carry on>
Also in your book, it is suggested to use a teaspoon of baking soda per 20 gallons weekly to keep the PH right. I also see on the Q&A page today to not use baking soda, but Kalkwasser instead, as baking soda is only temporary.
<again... the difference between making and maintaining water for invertebrate tanks versus fish only. The baking soda is fine and recommended (nicely inexpensive too) for simple fish only tanks where the unbalanced addition of carbonates (the baking soda) will not skew the dynamic of balance with free calcium (as from Kalkwasser) in the more complicated water chemistry of reef systems (assuming regular water changes are conducted)>
My PH was 8.1 all along, but I used the baking soda this week and it is now at 8.3-8.5. I am questioning myself now. Any clarification?
Thanks in advance. John Kummer
<8.3-8.5 sounds excellent...keep up the good work. Anthony>

Kalk info.... on WWM...
I was trying to find that article on the Kalkwasser dosing you mentioned, where was that again?
<Truthfully, I am not sure what you are referring to. If it was on www.WetWebMedia.com you can use the Google Search engine at the bottom of the page.>
Here is another idea I had---can I get away with adding any calcium or buffers if I do a weekly water changes?
<In theory if you calcium demand is low enough and your salt mix enriched (higher amounts of calcium and buffers than NSW conditions), but I would not count on this alone. There would be many other benefits to the weekly water changes, the least of which would be little to no need for other additives. -Steven Pro>

Heliofungia
Hi, great Heliofungia. I just bought one and it's pretty nice too. It's pretty big. I was wondering if there are any tips you can give me on keeping him. 
<must be kept on sand bottom... needs brighter light and less food than most Fungiids. Weekly feeding (or several times weekly if your lights are non-halide) will still be necessary with very fine minced meats of marine origin>
he seems to be doing great and loves the Kalkwasser additions.
<Kalk and buffer are needed for this and all corals... not Kalk alone>
stuff like light, current, nutrients, feeding , etc. anything would be just great, 
<please consult Eric Borneman's or my coral book for even more detailed info>
p.s. what do you think about adding the Kalkwasser. 
<I strongly favor it and describe a handy application tip in the BOCP1... also recanted (free:)) on Reef Central>
I have a 38 gal. but I just got a 90 and am so excited to set it up. I'm thinking about a dual 175 watt metal halide system and a euro-reef protein skimmer as my two most expensive equipment. Do you think I could get by with the Kalkwasser in a tank this size. 
<all three sound excellent>
Thanks, Jamie
<best regards, Anthony Calfo>

Re: Anthony, about slurry of Kalk
Anthony, I have your book and I have been trying to reach you to ask about the slurry of Kalk. I wanted to know if this is a better method of maintaining calcium and Alk then using a 2 part additive. 
<Kalkwasser is calcium hydroxide and only provides calcium. carbonates from a buffer solution are also necessary. Two part supplements like ESV have both and are balanced. They are more convenient but more expensive and they need you to start with a healthy balanced ALK/CA dynamic from go. They also do not precip phosphates or enhance protein skimming like Kalk. Still... they are far more convenient>
What are the risks involved in doing it this way? 
<my apologies, my friend... but we are buried in e-mail today and since you already have my book... it will save me from retyping <smile>. Please do revisit the sections/chapters on Kalkwasser, Calcium and Alkalinity and follow-up here if you still have questions>
I was just wondering because I went to the LFS and they told me that this was called dumping and it will not work. 
<they are mistaken or haven't been shown how to manipulate hydroxide safely and easily with a pH meter and calcium test kit. Many benefits and dangers to Kalkwasser. Please also do a keyword search here on the WWM engine for many pages on this topic in the archives. And do share what you learn with others <G>. As they say, give a man a fish, he eats for a day. Teach a man how to fish, and he eats for a lifetime. Best regards, Anthony>
Please clarify.
Thank you for your time.
Daniel