I take care of a 46,000 gallon pool at a small resort. For the last four months or so I cannot get the ph to rise to normal levels. I think part of the problem was the alkalinity was quite high, but I have that under control now. Even so, I've dumped about thirty pounds of soda ash/ph up in there and it still will not rise. I've tried two different test kits, same results. I've aerated the water using scuba tanks. I've been draining a few inches off the top every week and refilling.
Our fresh water comes from the ocean and is run through a reverse osmosis plant and is suitable for drinking. I've tested it for ph and alkalinity and both are in the correct parameters.
To my knowlege, the pool has not been drained and refilled for over six years.
I'm running out of ideas. Any advice or helpful hints would be much appreciated. Thanks!