Treating your saltwater like a chemist

[ebushrow]

I have a question relating to the pH of our mixed saltwater....have you ever tried to titrate the mix using HCL or NaOH (with a pH meter) as you would in a chemistry class? I know that people have there tanks at different pH's and dose to increase or decrease the pH....just wondering.

 

[Randy Holmes-Farley]

You mean to adjust the pH? That doesn't work to maintain pH of seawater because it alters the alkalinity.

FWIW, my DIY alkalinity test is a full pH titration down to about pH 4.2-4.5.

Adding OH- is what everyone does who uses limewater (kalkwasser) to maintain alkalinity (and calcium).

pH in seawater is determined mathematically by the alkalinity and the CO2 level. Adding acid or base lowers or raises that alkalinity.

 

[ebushrow]

Thanks Randy! I did see that you were using the HCL and NaOH for the alkalinity testing, Just wondered if you would be fine with using it to adjust the pH in newly mixed SW, which sounds like it will be ok.

 

[Randy Holmes-Farley]

Yes, but remember the effect on alkalinity is probably more important than the effect on pH.