I have a 90 gallon with juveniles peacocks and haps and my ph is good, maybe a bit high, at 8.4 to 8.5 but my KH is low. I use Cichlid Lake salt which raises the GH but not the KH. The rank has lace rock and cichlid sand to help buffer. How do I raise the KH without raising the PH. My tap comes out at 7.8 PH with low GH and KH.