Well just recently purchased a home with a pool and so far it has been going great except recently when my ph has begun to drift up to 7.8 to 8. I have owned the pool for 2 months now and this past week is the first time I have had to do anything with it, as it has stayed at about 7.4. I am not currently living in the house so I only have time to check it about 2 or 3 times a week, which has been fine until recently. Water has been crystal clear and the results below have been pretty consistent, just have not had time to work on getting the TA and CH down. I am using a combination of tri-chlor tabs and bleach as previous owner had a supply of tabs left when I bought house, I did just switch from one brand of tabs to another, I do not know the brand names, I will get those next time I head to house if it may be relevant. Any thoughts on whether brand of tabs can cause PH drift upward or any suggestions on what may be causing PH drift upward? Recently got a lot cooler here too, but pool is still open?