I am trying to dissolve aspartic acid into vinegar as use as a carbon source in saltwater aquariums. It does not dissolve.

I was told to increase the pH and it will work? What is the best way to increase pH with minimal negative effects?

Sodium carbonate seems to work at dissolving; however I may be reducing the acetic acid from 5% to something lower? Might also be creating an acetate? Calcium hydroxide could be a better choice for the aquarium but I can't seem to get the mixing ratio right?

  • $\begingroup$ Can I point out that in general we are not experts on saltwater aquariums. So if adding aspartic acid to your aquarium is a good idea or not is unknown to us. $\endgroup$
    – MaxW
    Commented Feb 20, 2017 at 2:03
  • $\begingroup$ I can only see one question in your text: What is the nest way to increase pH with minimal negative effects? Could you elaborate on what you would consider 'negative effects' might be? $\endgroup$
    – long
    Commented Feb 20, 2017 at 4:19

1 Answer 1


The good news is there is no good reason to add vinegar to your aquarium. You are correct that if you did, the addition of hydroxide to maintain proper pH would then neutralize acetic acid to acetate.

You can dissolve about 4.5 g of aspartic acid into a liter of neutral water. I assume you try to keep your saltwater tank at a pH of around 8.3 however, which should significantly increase it's solubility as aspartic acid is acidic, having a pKa of 3.9. This is the reason you could not dissolve the aspartic acid with 5% acetic acid, which still pretty acidic with a pKa of 4.8.

So the solution is to just use the slightly basic aquarium water itself, plus a dose of patience, to dissolve the aspartic acid. You could place it in a tea-bag next to your aerator or something if you wanted to isolate it and see how quickly it dissolves.


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