I have had this tank for a year and keep making small improvements. I dose kalk w/strontium every day to maintain pH at 8.0-8.2 using a continuous read pH meter which is calibrated. Nitrates, nitrites and ammonia are zero. Phospates are close to zero and I use a poly filter in the refugium for mechanical and chemical filtration (phosphates, etc.). Kent liquid reactor is added periodically. Calcium is 360. So everything seems like it ought to be fine but my corals are beginning to struggle (not opening fully or at all). I don't do anything to feed the corals (torch, toadstool, fiji leather, and colt). I change about 10-15% of water weekly sing RO/DI water and Reef Crystals. Does anyone have an idea why the colt and torch corals are doing poorly? Fiji leather and toadstool seem OK.