If you need a high PH for Afican cichlids eg 8.3 I would do things differently from if I needed a neutral ph 7.0 for american cichlids. Also it depends of how much I need to change it and/ or if I just need to keep it stable/buffered.
I personally use RO water so it has no buffer in it at all so like a clean slate. I do add minerals back but nothing that adds KH/buffer at first. What I do in this situation is put a handful or crushed coral in a filter bag in the filter, and this keeps my water just above neutral which suits the fish I keep.
I have in the past had occations where I have found the water has gone through the floor to about 4.5ph (before I used the coral) and I slowly added small amounts of baking soda to put it back up as fast as would be safe. Also if it went the other way I used a natural apple vinigar(very small amounts) without problems.
As others have stated, if you are trying to change your tap water with powders etc it is not worth it and you may find the PH bouncing all over and killing fish. Only use them if you have a ph away from what your water normally sits at in an emergency to neutralise the acid/akaline. If you need a permanent change use something else like coral substrate which has a gradual effect that is buffered. Also don't change too much water in one go.
Yes.. Of course use crushed coral to Stablaize the PH.. But you need to add a buffer to reach to at least 8.0 for Africans.. The only way to get there is add somthing.