Hard corals dying.. Need help

[cblair]

Reading through your post i think you may have forgot a few very important parameters such as nitrate, phosphate and alkalinity. If you are experiencing algae or cyano blooms it could be that your nitrate and or phosphate is too high. If you are not testing for these its possible. My next suggestion would be to test alkalinity. If it is too high or too low you could start seeing your sps loose tissue on their tips and it doesnt take long to see algae take over the dead area. This is just my suggestion if you are not testing these parameters to start asap. It will definatley help you in trouble shooting what is going on with your water. A good range to keep your alkalinity is anywhere from 7dkh to 10dkh+. For reference i really try to keep my tank on the lower side at around 7.5 to 7.8dkh because i have experienced tip burn at higher levels. Good luck hope this helps a little