The have a established 75 gallon mbuna tank and fish are now beginning to breed. My tap water after 24 hours is pH 8.0, GH 9 and KH 5-6. I have buffered to raise the KH to 10 but now curious if it's really necessary. SeaChem reports lower levels than most at 4-8. What would you folks do? I do 50% 5-7 day water changes.