High pH & TA-Losing Battle?

[Local409]

Here are my current readings:

FC=3
TC=3
pH=7.6
TA=150
CH=350
CYA=50
Salt=3200
Water Temp=91
Air Temp=100

Within a week my pH will be 8 and TA in the 170's. I am constantly adding acid. I tested my tap water: pH is 7.5 and TA is 225. Am I fighting a losing battle here? If I invest in a automatic acid feeder, will this eventually save me time and money? Any other suggestions?

 

[Guest]

This sticky will help you lower your TA. This will help keep your pH from rising as fast. This sticky will explain why raising your CYA with your SWG will give you better pH stability. IF you get your TA to about 60-80 ppm, raise your CYA to about 70-80 ppm, and then consider adding borates to 50 ppm it should help with your acid demand problem.

 

[Matt]

Part of the reason your TA is so high is that the rate of TA burnoff is tied to pH. It burns off much faster at low pH. With a gunite pool, you can safely lower pH to 7.0. At that pH, aerate (and be patient) to remove TA. When I wanted to burn off TA, I just lowered the pH to 7.2 or so (vinyl... so 7.0 was too low) and kept it there vigilantly. I didn't really have a good way to aerate, but I still burned off alkalinity just because of the low pH. It's faster if you aerate though.

I also have a pool that has consistent acid demands. I just use a lot of acid (almost daily). Keep adding acid until you get to 7.0. (Evidence that I've recently seen suggests that the method of addition of acid doesn't matter... so it's probably best to spread it around the pool and keep the filter/pump going so you don't get localized pockets of low pH.)

As the pH goes up, just add more acid to keep it down until your TA burns off to where you want it. The loss of TA is MUCH faster at low pH. When you're happy with the TA, let the pH rise on its own to where you want it (say 7.4 or 7.6). Be ready to add acid on an ongoing basis to keep the pH in range, and see the above post for suggestions on ways to reduce acid demand through buffering.

 

[JasonLion]

An automatic acid feeder will save you time, but it won't save any money. You can add the acid manually quickly (lowering TA), manually slowly (keeping PH reasonable), or automatically, but it will be the same amount of acid regardless of how you do it.

High TA fill water can be annoying. Your best bet is to build a particularly good aerator and get practiced at the lowering TA procedure.

Matt, acid lowers both PH and TA. Aeration raises PH and leaves TA alone. The net effect is that TA goes down and PH stays more or less constant.

 

[Matt]

Yeah, I had the same issue myself last year... very high TA after the pool company dumped way too much baking soda in, and my pH kept going up since I have a SWG.

I just kept adding acid to lower to about 7.2 and never let it creep up much until the TA dropped low enough. Just waiting lowered my TA. I didn't aerate because I didn't have any easy way of doing it. It would have gone faster if I had. However, even w/o aeration, there is some degree of outgassing just from the water contacting the air, especially if you get the pH down. I might have even gone a bit under 7.2, which isn't really recommended for vinyl pools, but it didn't seem to cause any problems.