High Ph and Low Ta

[jj in Dallas]

It doesn't make sense to me, but my ph is between 7.6 - 7.8 and my TA is 40 ppm.
Total hardness is 240
What do I do to get my TA up without increasing my ph?

My pool plaster is old and my pool is surrounded by crepe mrytles, so always
fighting debris. Use Pool Perfect plus Phosfree weekly.

Thanks for any help!

[chem geek]

You can use baking soda to raise the TA, but if your TA tends to rise over time I wouldn't raise your TA very much, perhaps to 60 ppm. If the pH is reasonably stable at the 60 ppm TA, then raise your Calcium Hardness (CH) level to compensate. Assuming your pool is not a salt pool (i.e. doesn't have 3000 ppm salt, say for a saltwater chlorine generator), then you can raise your CH to at least 300 ppm (but probably not higher than 400 ppm).

Are you using a hypochlorite source of chlorine such as chlorinating liquid, bleach, Cal-Hypo or lithium hypochlorite? If not, then what are you doing that is causing the pH to stay high?

[confussed]

i have a fibreglass pool approx 60 000 lts (salt)
Salt levels are fine.
Just have stablised the pool level.
Now i have low ta & high ph
Which do i tackle first or does it matter at all ?

[chem geek]

If the pH tends to rise, then just lower the pH with some acid and leave the TA where it is unless it's very low such as 50 ppm or lower. If it's 60-80 ppm, don't worry about it. If you raise the TA higher, then the pH will likely rise even faster. You can consider using 50 ppm Borates to slow down the rate of pH rise (it is a pH buffer that doesn't increase carbonates). Read Water Balance for SWGs.