Whats happening to my corals?

[Ruth]

Just a thought but have you tried taking a water sample to one of the LFS or a friend just to double check that your test kits are reading correctly? If it is an option can you move your corals to another tank (friend or spare) until you figure out what is going on? I know that one time I had a problem with some of my SPS and it turned out (I think) to be that one of my heater was leaching current into my tank from a loose wire on the connection. It was a very tiny amount but just enough to feel and I had 3 coral RTN before I took it out. Like I say - I'm not sure that was it but the RTN stopped when I removed the heater.