can't seem to balance alkalinity and ph

[suprstrmis]

new to pool maintenance so bear with me.

I started with alkalinity at 60 and added a 12 lb bag of baking soda over the course of a week or so and it is at 80 but my ph won't stop going up so do I need more alkalinity? I feel like for a 14.5k gallon pool that should've been enough to get my alk in better range?

my ph just wants to stay around 7.8-8. I add maybe about 1/6 gallon muriatic acid every few days and it just won't stay down for more than a day or 2 (at most)



14.5 k pool
white plaster
full sun
water temp about 70

 

[aussieta]

alkalinity at 60 was fine
ph at 7.8 is fine
the baking soda you added increased your TA, which has now caused your ph to climb
most pools will find an equilibrium around ta 50-60 and ph 7.6 to 8,0
stop fighting it and see where your pool wants to be
only drop your ph from 8,0 to 7.8

 

[mgtfp]

The intended function of "TA" is to buffer pH fluctuations. More precisely to protect pH from crashing down. This is particularly important when chlorinating with trichlor (which is not recommended due to the CYA accumulation), as trichlor is quite acidic.

But by adding baking soda to increase TA you carbonate the pool, and like in an opened soda bottle, the dissolved CO2 wants to outgass to reach equilibrium with the atmospheric CO2. In the process pH rises. (Carbonated water tastes more acidic, when the CO2 bubbles out, the water tastes less acidic.