Help with PH

[Frank]

My total alkalinity was low I added Kent super buffer dkh until It was 8, but my PH is now about 8.8 did i use the wrong product. Also calcium leve droped. This was after a 18gal water change in a 60g tank

 

[Murfman]

I would test again, that doesn't sound right. The buffer is supposed to bring your tank between 8.0 and 8.3. Test again, you may not have let it mix enough.