View Full Version : Lowering Alk in Hot Tub
csevel
07-03-2006, 11:29 AM
I want to lower my alkalinity in my hot tub...is it safe to add muriatic acid to the spa with the jets bubbling? What is the calculation to lower alk by say...40ppm. How much muriatic acid to use? I saw a calculation somewhere in these threads but I can't find it anymore:
waterbear
07-03-2006, 08:43 PM
How many gallons is your hot tub.? It is safe to use muriatic acid but you will be dosing by teaspoons, tablespoons, and ounces and it is very easy to overshoot. Dry acid is easier to measure for the small volumes of water in a hot tub. Procedure is the same as for a pool. Lower the pH to about 7.0 then aereate to decrease TA! The air jets and bubblers (if you have them) make efficient aeration very easy! Here is the thread that explains it
http://www.poolforum.com/pf2/showthread.php?t=191
csevel
07-04-2006, 11:10 AM
It's a 500 gal. tub. The PH is at 7.8 and the alk is at 220. All other numbers look good. How much muriatic acid should I add to lower the alk?
waterbear
07-04-2006, 10:53 PM
It's a 500 gal. tub. The PH is at 7.8 and the alk is at 220. All other numbers look good. How much muriatic acid should I add to lower the alk?
I would not add more than 1/2 oz. at a time (1 tablespoon) and then check the pH in about 20 minutes of filter run time. Repeat until the pH is at about 7.0 and then open up the air jets.