hmm, my biggest problem was that I was having issues keeping any SPS alive any length of time. Last year after we did some renovations I started having issues in the tank only with corals, all the fish were fine. Corals looked great for the first week or so. But then in a few weeks they start to brown out, bleach, polyps retract and eventually RTN one day. LPS would start out great and by about the 3rd week they don't show as much polyp extension, eventually retract and receded only to die maybe a month later. I sort of ignored it for in the beginning and was just leaving the tank without corals for a while just being busy with life. Around October/November last year I decided to get serious and get the tank back in shape.
After speaking with a few friends who had remarkably similar issues with their coral when carbon dosing, I decided to stop carbon dosing and using GFO. I also decided to switch salt. I had been using Oceanic for something like ten years, but for some reason the last year or so, the animals didn't look better after a water change, they looked a little worse. Corals just seemed a little more retracted from what they had been in the past. I changed my salt to Red Sea Coral Pro.
So I pulled off the doser and did a few water changes and low and behold things looked better. Polyps were out a little more.
So at this point encouraged by the first glimmer of hope, I go all out. I start performing water changes twice a day for the first two days and then every day for a week. I was making so much ro/di water I killed my RO module in the middle of it and had to buy all new DI resin and a new RO filter. So after I changed out about 450 gallons of water, then I dropped back to twice weekly water changes and then once a week. Boom! tank looked great. So I started putting some frags in to se how they would do and they did much better. But I was still having issues with RTN and tip burning. So I started working getting the tank stable. Alk was fluctuating too much, and that actually took me a few weeks to get under control. I was just underestimating how much alk my ca reactor and kalk reactor could put in the tank, even at very low settings. So once i realized that I shut off the kalk reactor and ran the Ca reactor at it lowest settings and I was finally able to get the alk steady. Things were looking better but I was still not comfortable with how frags were doing in the tank. So after talking to some more people I switched salts again back to Instant Ocean (what I used to use like 10 years ago). Changed out about 300 gallons in a week and all the corals looked much better. From there the tank has been doing so much better I tend to think that it was the RSCP salt that might have been giving me issues for the last few months.
Right now my tank is very stable, last weeks tests of the parameters were.
SG:1.026 Alk:7.8 dKh Ca:470 Mg:1410 NO3:5ppm PO4:0.01
