Can't balance pH and TA

JLA956

Bronze Supporter
Oct 24, 2017
10
Dallas, TX
I just filled my hot tub for the season and I'm having a heck of a time getting its pH and TA to the correct levels. I'm following the guidelines outlined in Nitro's article " How do I use Choline in my Spa (or pool). I'm trying to get my TA to 50 ppm like he recommends but when I do that my pH goes above 8.0. I then use PoolMath (PoolMath) to figure out what I need to do to get it back down around 7.2. I add the appropriate amount of Muriatic Acid and let my spa run for about 15-20 minutes then test it. The pH is usually spot on but when I test the TA it's down around 20 to 30 ppm.

So, I go back to PoolMath and follow the directions to get my TA up to 50 ppm. I add the appropriate amount of baking soda, run the jets for 20 minutes and then test it. The TA will be spot on but the pH is now well above 8.0 - I say well above because when I add the proper amount of Muriatic Acid according to PoolMath it only lowers it to about 7.8 or 7.6. I have to add more acid to get it down to the 7.2 range that Nitro says it needs to be at. So, I test again and the pH is OK but the TA is back down to 20 or 30 ppm.

I have repeated this process at least a dozen times over the past two days and I'm just chasing my tail. I've even let the tub sit overnight to settle out but still have the same issues. I've also let it sit about 30 minutes after the jets cut off but sill the same results.

Should I quit worrying about the TA getting to 50 ppm and just settle for the pH to adjust out to 7.6? I know that a low TA will cause my pH to be unstable but as of now I don't know how I can achieve both. Also my CH is a steady 120 ppm no matter what I do with the pH and TA so it's right where it needs to be. Again, this is a fresh fill in a clean tub. I've never had this problem in the previous two years so any help or advice would be much appreciated.
 

tim5055

Mod Squad
TFP Expert
LifeTime Supporter
May 11, 2014
10,415
Franklin, NC
In my stand alone fiberglass spa I seldom test TA or CH. I know that I'm going to replace the water in 3 - 6 months, so no big deal.

FC, CYA and pH are what I watch.

To be honest, I have never used acid in a tub, my pH drops and I'm having to bring it back up.
 

JLA956

Bronze Supporter
Oct 24, 2017
10
Dallas, TX
OK - thanks for your help. I'm like you, three months from now I will drain and refill the tub so I'll just focus on the pH instead of the TA.