I thought the rising PH was due to the chemical reactions of the SWG as indicated here: http://www.goldlinecontrols.com/Elec...orination.aspx

The hydroxide ions on the cathod increase the pool water PH.

As for my experience, I have no water features at all and my PH can go from 7.2 to 7.8 in less than a week.

One other thing not mentioned which could have a significant effect is that fill water, such as mine, can be quite basic. Mine is over 7.8 in PH.