pH constantly increasing with SWG


New member
May 28, 2019
I switched my pool to a SWG about 2 months ago, and I find my pH constantly hovering around 8.0. I have to add about half a gallon of Home Depot Muriatic Acid about every 2 weeks to get it down to around 7.6. I have gone through 2 gallons in about 2 months now. 21,000 gallon pool. Any ideas what is causing the constant increase in pH? All other numbers are in line with where they should be.


Gold Supporter
TFP Guide
Jul 21, 2013
Northern NJ
Welcome to TFP.

How were you chlorinating your pool before the SWG? Trichlor Tablets?

Trichlor tablets contain acid which was lowering your pH. Now you need to manually do what the trich was doing.

A gallon a month of MA is pretty normal. Some folks go through that in a week or two.

What type of pool do you have? Plaster? Vinyl?


Mod Squad
LifeTime Supporter
Jan 17, 2012
Evans, Georgia
A *lot* of folks using SWGs find that their pool pH likes to stay around 7.8. I'd try taking it there and seeing if it stays longer than when you aim for 7.6.

Without knowing what your TA is, its hard to say if there is a problem or not. A high TA will always strive to pull the pH upwards.

7.8 is within suggested parameters.

Maddie :flower:


TFP Expert
Mar 2, 2011
If the pH keeps going too high, the TA is too high.

What are all of the chemistry readings?

What type of pool do you have?

What test kit do you have?
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New member
May 28, 2019
Sorry for delayed response. Been away. TA is 60. PH is at 7.8. FC is 4.5, CH is 210. CYA is around 70-80 cant recall, but not high. Doesnt usually exceed 8.0. Typically if it is super pink. One drop of the Acid Demand drops it to 7.8, so its never too far off. I guess if adding 1 gallon a month is normal, that makes sense. I used trichlor tablets before, so makes sense it was more stable before I switched to SWG. This is a plaster Pool