Ok, so my alk is 16.5 and my Ca is 430. Through all of my research, I have been led to believe that an alk this high would not allow for a Ca this high. If ur alk above 12, then Ca will be below 400, this is what i read on many sites. am i correct in reading that Ca should be 400-450 and alk should be 8-12? If so, is it ok for my alk to be a little high(16.5) as long as my Ca is acceptable(430)? Or do i need to do another water change to get my alk down, and then work with my Ca from there? erikharrison, you researched my last forum. I'll bump it up so it will be near this one for convenience. Thanks to all once again, Josh