Chem challenge! rasing pH without raising Kh?

[mab]

I need to raise my pH and lower my KH at the same time. Any of you seasoned chemistry wizards know how to accomplish this? any suggestions will be much appreciated. Kent Superbuffer just makes matters worse (raises KH and Alk even higher) I tried plain sodium bicarbonate (baking soda) but as you know the raise in ph is only temporary. The high KH is also affecting Calcium levels negatively.

Tank specs: 55 gal reef 5 sm fish, many inverts, live rock, established 1 year, Ehiem Pro, Remora skimmer w/ carbon filtration, UV, 4 powerheards behind Wavemaster Pro. Amo 0, nitites 0, nitrates <15, calcium 330, Kh 17! (want lower 8-10) , ph 7.95, (want higher 8.1-8.3), use RO/DI and Kent Seasalt exclusively.

 

[mgk65]

I think your parameters are not too bad. How do your corals look? Are they in distress?

What test kits are you using?

If you up you Ca and let the dKh drift down, that would work.

An easy answer is to do a substantial water change; it will always help ionically imbalaced problems.

mgk

 

[mab]

Corals look a somewhat distressed. BT anemone whitening. I'm using Tropic Marin test kit for Calcium and KH and an electronic ph monitor, just calibrated. The ph keeps drifting back slowly.

 

[Anonymous]

i second the recommendation for large water change-this will both lower your alk,and keep your ph stable.your corals and other inverts will love it, too!

then the real trick is to stop what you did to get to that situation in the first place :wink: how did it happen?

 

[ReefLion]

If you have high alk but low pH, then you have an excess of some ion in the water compared to NSW (one that doesn't drive pH as high but keeps it stable at lower pH). I don't know what it is, but think about what you've been adding and test out the possibilities. In the meantime, water change is the best and easiest solution, as others have mentioned.

Someone correct my chemistry if necessary.

Tim

 

[Anonymous]

I had a simular problem on my 80gal. My alk was where yours is and so was pH and calcium. I had read that excess CO2 could hinder your pH. I did their suggested test of taking a gallon of tank water and aerating it for an hour with an airstone. I measured the pH before and after with my meter. I was amazed at the difference. I did more research and found that small houses like mine can build up C02. I began aerating my refugium and upgraded my skimmer to a LifeReef, which is a air producing machine. I improved the ventilation in the house to bring in some fresh air. I also started leaving the fans for the lights on 24/7 to aid in gas exchange. As my caulpera grew, the pH stabalized even more. I did 1 large water change to drop the alk a bit, and started dosing my kalk 24/7 instead of just at night. That was 6 months ago and now my pH ranges from 8.0 to 8.3. The alk/calcium problem straightened itself out with time, and now I just use buffer as needed for alk. I believe my condition came about by using too much buffer trying to raise my pH, and my pH problem was excess CO2.

Regards, Eric

 

[liquid]

Here's a couple good articles for you to read:

http://www.advancedaquarist.com/issues/ ... 2/chem.htm
http://www.advancedaquarist.com/issues/ ... /short.htm

Shane

 

[randy holmes-farley]

There are only two ways to raise pH and without raising alkalinity (I believe):

1. Remove CO2 from the system somehow
or
2. Replace your current alkalinity supplement with one that has a larger pH raising effect. Limewater is the best you can do in this method, but carbonate-based additives also work well (such as the original B-ionic).

 

[mab]

Thanks everyone for the great advise, also thanks to Liquid for the referenced articles which have cleared some things up for me. I don't think I have a CO2 problem as ventilation in my home is very good and have good dissolved oxygen levels though vigorous currents created by 4 powerheads and the wavemaker, additionally, the tank glass covers stay open to allow for cooler tank temperatures though evaporation.

I must have excess carbonate ions. I will stop using all buffers as of now while raising and maintaining calcium above 400 (not as easy as it sounds without precipitation)

As for the quick fix... what is considered a LARGE water change? 30%, 50% more? I have been repacing 10-20%/week already.

What a usefull and helpfull board, thanks again.

 

[Anonymous]

minimum 50%

 

[randy holmes-farley]

FWIW, if the tank has dKH 17 and a pH of 8, then the tank is overloaded with CO2 (unless you are using Seachem salt with excess borate). Maybe not the house, but at least the tank.

 

[mab]

Thanks Randy, how do I reduce the Co2 in the tank besides vigorous water agitation?

 

[randy holmes-farley]

First, do a test to see if it is the tank or the house (or a faulty kit).

Put some water in a cup, drop in a pH probe, and aerate it with a bubbler for an hour or so. The pH will climb as CO2 is blown off. Try this inside and out.