Can anyone share their experience with CRS keeping in the water with high PH?
I went though many Japanese website and look like their water is below PH 7.0 (6.4 - 6.

I know I can get the bottle of chemical from PetsMart or PetCO to lower down the PH. But then with each water change or adding water, I need to re-adjust PH. Need to adjust PH - that means I may cause PH swing in a short period of time if I fail to do it very carefully. With angelfish, a PH 0.5 swing will definitely cause serious problem. What about shrimps? (both CRS and cherry red shrimps)
Also I have placed a few pieces of cuttlebones in the tanks which are supposed to buffer PH and KH. So my guess is the chemical will not function to lower down the PH unless I remove the cuttlebone pieces. Am I correct?