Coral dying rapid tissue necrosis???

[baloutang]

Hi,

I've been a "reefer" for little over a year. Within that year, I've lost many corals due to various factors.

Lately, I had a hammer coral that completely melted away. I did do 2 idodine dips, but these never ever help.

Is there any way to prevent corals from dying in this fashion? Only a piece will start to fade and then the next thing I know large chunks are just dying off.

My tank params have remained consistent. I've not added any new livestock to the tank for well over 6 months. I do monthly water changes as well with only RO/DI water as well as top offs. My lights are only 3 months old so no need of changing as well.

Temp 79F
PH 8.0
Calcium 400

I run a wavemaker as well as a chiller and heater to keep the temperature constant within the tank.

Let me know your thoughts and how to prevent this from happening to any more corals.

Thanks,
Dave