lowering alk

[d branch]

I have heard you can use vineger to lower alk but will it lower ph also? Besides a good water change what do you recommend?

[EvilMel]

Hey Dennis why would you want to lower alk?

If it's high I usually just leave it, but most people would probably do a water change I believe.

[SmartWrasse]

Vinegar contains Acetic Acid so it should lower the pH. If your calcium is low, you may want to bring it up to normal or high normal and see if that affects the alk (sometimes lowers it a skosh).
I would prefer water changes over adding acid. I don't have the links for them at work, but I have sent around links to the R. Holmes-Farly online article about how to address corrections of calcium, alkalinity and pH. Maybe someone else has the link they could post to the thread.

[satman]

The main problems with vinegar is that you don't know the strenght of the acetic acid, although it normally is quite low, or what else is in it. So it is mainly blindly adding and testing.
The link that Mike and I both like for Ca/Alk control is:
http://www.advancedaquarist.com/issues/nov2002/chem.htm

It is referenced in my pH article on the Articles page.
Gould

[EvilMel]

yeah that is a great article.

[d branch]

I was asking the question for someone thats is having a high alk problem and thought of using it. My first answer was I would not put it in and do a water change. Check the buffing for the alk boost. You can be too high on alk, with out good alk the calcium, ph seems to fall or does not hit a good level. I did not know what to say what vinegar does?thanks dennis

[satman]

As the pH rises so does the alk level that it can handle, but it can handle quite a bit more for small rises in pH (see graph in pH article). You are right, 10-15% water change is the best place to start. If the alk is not exceptionly high it will naturally come down within a few days, if the other conditions are right - ie temp, salinity, Ca, and pH. Also make sure there is good air exchage with the water - something rippling the surface of the tank to allow CO2 into the water and acid creation.

[Pandarian]

Originally posted by SmartWrasse
Vinegar contains Acetic Acid so it should lower the pH.

I thought vinegar IS acetic acid? its just diluted to usually ~5%? haha, two semesters of organic chem and I still cant answer that. d'oh :hammer:

[EvilMel]

Hell Donny I didn't even remotely think of it either.

Of course my organic chemistry sequence was like way longer ago than yours! (so was biochemistry and general chemistry).
Thank god.