TA question

[Mamamartini]

Hello : ) My TA has been gradually decreasing, and after a particularly heavy rain recently, it dropped to 80. I added 12 pounds of baking soda on the 30th, and I just rechecked it and it's only at 90. Is it common that it doesn't increase as expected? I mixed it with some pool water and divided it between two returns. Does it take longer than 48 hours to register completely? It was a brand new bag from Costco. Thank you!

Other numbers:
CYA - 45
FC - 4.5
CC - 0
CH - 250
PH - 7.4

 

[DeanP66]

80 is a good number for TA. No need to increase it at all. I have mine at 70 currently. It will increase over time slowly as your pH rises naturally.

 

[Mamamartini]

Oh, the materials that came with my test kit said manually chlorinated pools needed to be 100-120. That's why I was trying to get above 100.

Thank you!

 

[Donldson]

Your signature shows a chlorine feeder, are you using pucks for regular chlorination? If so then yes, it is best to keep your TA above 100 because the pucks are very acidic and the higher TA helps keep your pH from dropping too quickly. However if your primary source of chlorination is liquid chlorine then it is best to keep your TA lower, in the 60-90 range for more stable pH.

As for why it didn't register, no as long as the baking soda was completely dissolved then it should register correctly after it mixes, usually within a half hour. It is possible that your TA continued to drop during that time for whatever reason, or perhaps something as small as a minor testing variance. Either way I would trust that you are only at 90.

 

[Mamamartini]

I use the chlorine feeder only when I need to increase my CYA with pucks. Otherwise I normally add bleach.