Magic pH break point?

[steveinaz]

For the last 3 weeks my pH has held at 7.5. For the last 2 years I have had to use 3 cups of Muriatic every Saturday to keep it in check. This seems a little suspicious---I just got a new bottle of pH phenol red (Taylor kit) and my pH has been reading perfect ever since I got the new bottle.

Does pH finally correct itself? Should I be concerned about this?

[waterbear]

Where is your TA?

[steveinaz]

80ppm. It just seems strange that all of a sudden pH would stabilize.

[waterbear]

Has your TA always been at 80 ppm or has it been higher in the past?

[steveinaz]

It was around 120ppm last season.

[waterbear]

and there is your answer. High TA is one of the contributors to rising pH. When using stabilized chlorines like trichlor and dichlor a TA of aourn 120 will lead to pH stability because it ofsets the acidic nature of the chlorine source. With unstabilized chlorine sources which are more pH neutral, running a lower TA (90 ppm ot lower) leads to more pH stability since there is less outgassing of CO2.