Acetic acid

[Jay Jolicoeur]

My background is Chemistry. I need to lower my pH.  I have read discussion where people are using Muratic (Hydrochloric acid), Sulfuric Acid, and Phosphoric Acid.  Has anyone used vinegar or Acetic acid.  I think that it will work well. It is a weak acid and will form a buffer.  Any thoughts.

[Robert C. Wood]

I am not very familiar with using all those types of acids but the real question would be does the acetic acid or vinegar kill the bacteria in the system? 

[Vlad Jovanovic]

Any of the three acids that you listed would be better than using acetic acid. Opinions may vary as to particulars, but it does seem that both acetic and citric acid do have anti-bacterial properties that go beyond a pH related anti-microbial effect...that, and they are very 'weak' acids, so depending on the kH value of your water, your lookin' at having to use a whole lot of vinegar (all things being relative of coarse) and introducing a relatively well documented anti microbial agent into an environment where you are trying to foster microbial life...Seems pretty silly don't it?

Now we can wax poetic in tomes about whether phosphoric acid is 'better' than hydrochloric acid (the later being my personal preference), but adding either would still be better than trying to use vinegar out of some misplaced assumption that it is somehow 'safer' or more 'natural' than either muratic or phosphoric acids...

What are the kH and pH values, and what volume of water... 

If you are fishless cycling in anything other than 'liquid rock', don't bother...your better off for now with the high pH IMO. 

[Jay Jolicoeur]

I appreciate the input.  Did not consider the antibacteria properties. Makes sense.