Yea most buffers are designed to allow the ph to be risen safely while not affecting alkalinity. How they can claim this is beyond me since carbonate hardness is a function of PH level and stability so hmmm?
I try to add marine buffer for ph weekly. I also dose a little mag, cal, and alk
(the next day to avoid precipitation) but I add 1/3 recommended dose. Along with a 5-10% PWC
every 7-10 days.
What test kit do you use? I would bring a test into your lfs
just to be on the safe side. I have read that a swing in ph by even .2 can be very stressful or even fatal to fish. Have you noticed a change in behavior from the inhabitants?