PH too high

[jbuckste]

Hi, all. Say, I am struggling week after week to keep my PH level within the normal range. It always runs above 7.8. I have to add almost a quart of muriatic acid every week to keep it down.

Is this normal?

Jonathan

[waste]

Jonathan, if you have a SWCG, this is about normal if you keep your TA over 100. Waterbear, chem_geek and PatL have posts on this. If you lower your TA to the ~70ppm range, the outgassing causing the pH creep will minimize so you would need to use less acid If you have a plaster or pebbletech pool, you may need to adjust the calcium down to allow for this.

I'm far from an expert on this, but it's what I remember

[chem geek]

If you lower the Total Alkalinity (TA) significantly, then you may have to raise the Calcium Hardness (CH) UP somewhat, not down. Also, the use of Borates can also help reduce the rate of pH rise significantly.

[CarlD]

This very common w/SWGs and new concrete pools. It's counter-intuitive but the solution is correct.

[waterbear]

Not counterintuitive at all once you really understand what is happening in your pool!
Lowering the TA means lowering the carbonation of your pool (all pool are over-carbonated on purpose). This means there is less carbon dioxide in the water that can outgas. Outgassing of CO2 is one of the main factor that makes the pH rise. (There are others but they are not the primary reason pH rises, with perhaps the main exception being curing plaster which introduces alkaline material into the water.)