I've had my tank up for about 8 months now and my calcium/alk is driving me crazy. My calcium has always been over 500, usually around 540. My alk is always low despite using Kent super buffer. When I first started the tank, I used a product called BioCalcium by Tropic Marine, I have dripped Kalk off and on. I have not used any kalk in the past 3 weeks. Yesterday my calcium was 520 and alk 6 dKh. I have done water changes without any benefit. I have a DSB of aragonite, most of my rock is aragocrete. My coralline algae started grwoing about 2 months ago and then suddenly stopped and bleached out. I have also noticed a fuzzy brown algae growing on the sand, but only in areas exposed to light. I added Phoszorb to the sump about a month ago and run carbon in the sump as well. Anybody have suggestions or ideas? My LFS says that high calciums are common the first year as calcium leaches out of the sand bed, but I'm afraid that this is causing my corals to just not thrive. Help me.:doh: