High PH and Alk

[Jimsreef]

My alk and ph has risen to alk 13 and ph to 8.6 at night and 8.8 during the day. I was adding purpleup before the rise. How do I get it back down? Jim

[stewie24]

Do partial water changes. I'd do perhaps 3 gallons a day (if its the 90 gallon in your sig) until it gets to the target where you want it. Change a gallon in the morning, then wait a few hours and check the alk/ph. Then perhaps change a gallon at dinner time and then again before bed. The key to lowering alk is to do is slowly so it doesn't shock your system.
I'd also check your calcium.
Stewie