Best Chemical To Decrease Ph

[Lindsey79]

I have a spa that uses a bromine system (many thanks to Waterbear's step-by-step directions on the 3-step bromine start-up --- that was very, very helpful!). After reading through so many threads on this forum, I have a question of my own. I've seen many references to "dry acid" to reduce pH. I've just used something called "pH decreaser", but now I'm starting to pay far more attention to the actual chemicals. Mine is sodium bisulfate. Is this the same as dry acid? Is the ideal chemical to decrease pH? If not, what are other suggestions? Thanks in advance!

[quantumchromodynamics]

Mine is sodium bisulfate. Is this the same as dry acid? Is the ideal chemical to decrease pH? If not, what are other suggestions? Thanks in advance!

Yes, sodium bisulfate is dry acid. It works fine. However, I prefer 31.45 % muriatic acid (hydrochloric acid). You can get a quart at any hardware store.

[waterbear]

If your tub is 400 gal or less then using sodium bisulfate might be easier than using muriatic acid since such small quantities are required. The dry acid is easier to measure in small quantities than the liquid muriatic acid, IMHO. Otherwise, I agree that muriatic is preferable.

[Lindsey79]

If your tub is 400 gal or less then using sodium bisulfate might be easier than using muriatic acid since such small quantities are required. The dry acid is easier to measure in small quantities than the liquid muriatic acid, IMHO. Otherwise, I agree that muriatic is preferable.

It is a smaller tub -- only 375 gallons. But thank you for differentiating between sodium bisulfate and muriatic acid and just letting me know that I can pick it up at any hardware store. Trying to translate "pool products" has proven to be more difficult than I anticipated and I really appreciate all the real life translations/alternative (baking soda, borax, etc.). Much thanks to you both!

[spawn]

I picked up a pool size (7 lbs) bottle of dry acid (pH minus) at Lowes (they have pool chemicals in their garden section) for a very low price (can't remember how much - <$10?). I put in a couple of TBSP every two or three weeks because of PH creep. I also use it when I balance the tub after a fill because I start with high PH from the tap.