Thanks in advance for you help. I've just started up my SPA and trying to balance pH and TA before I pour in the start up bromine and stuff. I got the TA and pH to desired level but pH is high after SPA heating cycle. I've set my SPA to heat (slow speed) between 9PM and 6AM, and when I check the following day, pH is really red. TA is at same level. Why is pH doing this? I know about the aerate increasing pH but none of the jets are above the water line. I use acid to lower pH to 7.2, but it goes high again after SPA heating cycle. TA is good. I can't keep adding acid everyday because acid will also lower TA and then I need to add baking soda to raise TA and it's just a infinite loop. Please help. Thank you.