Water hardness parameters

Im starting a planted community tank. Right now there's just snails and shrimp for livestock. I have very soft tap water and I'm struggling to get my GH KH and PH in line. With plain tap water GH is low like 25-30ppm KH is 0-20 and PH is neutral like 7.0

I tried adding a cuttle bone to the filter which raised the GH to 75ppm and the PH was okay at 7.5 but KH was still 0-20

Next I added some crushed coral into the filter and now my GH is 75-100ppm kh is up some at 40-60 but PH is getting too high at 8-8.5

Help please