zanebaby

I also have the issue of constant high pH and low TA. I use monopersulfate and Nature 2 to kill bacteria. I have never had the issue with TA and pH until recently and I've had the same spa for over 20 years. My question - can a faulty ozonator or heater cause the pH to increase? I set and check calcium hardness regularly but it's never an issue. I've tried draining and refilling a few times and within a couple of hours the pH is shooting up. I've tested my tap water and it's always very good with the pH about 7.6 or so.