How much vinegar to lower pH in tank

[Flipper1]

Hello Randy. I've got a 7 bowfront nano in which I've recently begun dripping limewater on a regular basis, as my calcium and alkalinity needed adjustment (zone 2, per your article). I mix 3 level tsp. of Mrs. Wages with 35 ml. distilled white vinegar to each gallon, and I drip roughly 6 ounces per day to the tank.

My pH, consequently, has risen to an undesirable level, and my Salifert kit measures 8.6. Can I add a small amount of the vingar directly to the tank? If so are there guidelines or a formula I can go by in order to lower pH X number of points per Y number of gallons by adding Z amount of vinegar?

If vinegar straight to the tank is not advisable, do you have any other reccommendations as for keeping pH in check when dripping kalk?

As always, thanks!

[Randy Holmes-Farley]

Yes, you can add it directly, or in the limewater. I discuss how and how much in this article:

High pH: Causes and Cures
http://reefkeeping.com/issues/2005-03/rhf/index.htm

More aeration and using soda water are other good options.

[TwistedTiger]

Originally posted by Randy Holmes-Farley
[B]Yes, you can add it directly, or in the limewater. I discuss how and how much in this article:

High pH: Causes and Cures
http://reefkeeping.com/issues/2005-03/rhf/index.htm

I agree with "I recommend adding 1 mL of distilled white vinegar per gallon of tank water to initially reduce pH by about 0.3 units ", but that will be very temporary if dripping kalk is the cause of your PH problem. I had to add around 125mL of vinegar to 2tsp kalk dissolved in 1 gal H20 to reach an acceptable PH range so my kalk drip wouldn't cause a ph rise in my already top of ph range tank. Adding 45mL still had my kalk solution with a ph well above 12.

[Randy Holmes-Farley]

Yes, if you believe that it is a long term concern (which it often is with limewater), adding it into the limewater is a fine way to go.

Adding 45mL still had my kalk solution with a ph well above 12.

Yes, that should be the case. Vinegar has much of its pH lowering effect after it enters the tank and is decomposed to CO2 by bacteria.

[Flipper1]

Yes, I gathered from the article that as the bacteria metabolize the acetate, CO2 is produced. Does the 45 mL./gal. that you practice, Randy, seem to produce desirable end results as far as keeping pH in an acceptable level? And, if this is the case, is Twisted Tiger's technique of adding 125 mL to the mix going to send the tank into overdrive, similar to adding sugar or vodka to a tank?

Further, have you ever tested any sort of radical ideas, such as mixing calcium oxide or hydroxide into soda water? Maybe you, as a chemist, already know whether this will work or not, or what the results might be. But such things come to mind when I read about how some of these substances react with and counter each other.

[Randy Holmes-Farley]

Does the 45 mL./gal. that you practice, Randy, seem to produce desirable end results as far as keeping pH in an acceptable level?

I don't add vinegar to my limewater, but that amount is intended to about balance the acid produced with the base added in the limewater, at least according to Craig Bingman's old calculations, and many people find it to work fine:

http://web.archive.org/web/200304181...io/default.asp


Adding soda water to lime will result in precipitation of calcium carbonate.

[Flipper1]

Thank you!

[Randy Holmes-Farley]

You're welcome.

Good luck.

[TwistedTiger]

Originally posted by Flipper1
And, if this is the case, is Twisted Tiger's technique of adding 125 mL to the mix going to send the tank into overdrive, similar to adding sugar or vodka to a tank?

I'm definitely not advocating that everyone start using the amount I am, nor am I claiming that I even know what I'm doing, Randy is definitely the expert here. I was just trying some different things that may help me keep my PH a little lower while still being able to drip saturated kalk. I've been adding the 125mL for 3 months now to a 75gal SPS dominated tank with no visable ill effects. I have had no algae blooms or cloudy water and all corals look great. It has helped lower my high end ph slightly so I will continue to experiment. It's a discussion I would like to see continue and hear other reefers observations from vinegar additions to their tanks.

[Randy Holmes-Farley]

FWIW, adding a lot of vinegar will drive bacteria, just as vodka and sugar can. Whether that is good or bad depends on the aquarist and the tank.

[Flipper1]

I can see how this could be benefial or not to a system. I'm not likely to add that much viegar, as I'm working with a very small environment to begin with, and subtle changes can be big ones in this tank. Out of curiosity, though,Twisted, have you measured the pH of your mix before dripping it? If so, what kind of numbers are you getting. It seems to me that if you're bring the pH way down, it would not be so critical as to how slow the mixture is added.

[Randy Holmes-Farley]

It is not normal to add so much vinegar that the pH is below 12. That implies an excessive dose of vinegar, IMO, and is akin to dosing calcium acetate. That can actually drive down pH, and also uses larger amounts of O2.

[TwistedTiger]

Originally posted by Flipper1
Out of curiosity, though,Twisted, have you measured the pH of your mix before dripping it? If so, what kind of numbers are you getting.

It depends some on the ph of your RO/DI water but my mixture ended up around 8.8. Like Randy said 125mL is not a normal amount to add but so far it is working for me. My daytime ph still ranges between 8.4 and 8.5 while my nightime ph is usually between 8.35 and 8.4. I have a fuge that stays lit at night to help stabalize ph and my kalk drips 24/7.

Originally posted by Flipper1
It seems to me that if you're bring the pH way down, it would not be so critical as to how slow the mixture is added.

Probably not but I prefer adding both the kalk and the vinegar a little at a time. About one drip per second from my dripper keeps up with my evaporation and keeps me from making sudden changes from all at once additions.

[Randy Holmes-Farley]

[B]It seems to me that if you're bring the pH way down, it would not be so critical as to how slow the mixture is added. [?B[

It can be in the sense of O2 depletion, which might happen if acetate is added too fast in large amounts, but if spread out is less of a concern as O2 can come back in from the air.