Ph won't stay up

[my4boys2002]

I have been raising my ph every few days, chlorine has been good. I can't figure out why my oh won't hold this year. I'm in new England we have had normal temps. My neighbor is noticing the same thing this year. It's driving me crazy

 

[JasonLion]

What is your TA level? Also, what are you using as a source of chlorine (tablets, SWG, bleach, etc)?