HELP! Need suggestions!

Hi everyone- HELP!

I am a longtime reader of this forum, and this is my first post.

Before pleading for your advice, I'll give you the background on my tank (so you experts know what you're dealing with)



I have a Nanocube 28 HQI, and have done a lot of work to it including:[*]Custom overflow[*]Custom 15g sump/refugium (Chaeto)[*]Eshopps Skimmer[*]UV[*]Hydor Koralia Nano powerhead[*]Heater[*]Fan[*]Apex controller.



It has been cycling for about four months, the stats are

Nitrate: 0

Nitrite: 0

Ammonia: 0

Temp: 77-78

PH: 7.9

Calcium: 420 ppm

Salinity: 1.024



I have put in two common clownfish, one coral beauty, assorted mushrooms, and overall it HAS been going great.



Recently I've come upon a bunch of issues, which I cannot explain.




My month old hammer coral is dying- shrinking and not looking healthy.



My Goby died for unknown reasons; it looked whole so i believe it may have been a water issue (???)



the larger clownfish is picking on the smaller clown, to the point that quite a bit of Its fins are missing and it always stays in the top corner of my tank.



Its been going so well for the past two months, and I can't understand whats happening!



Help!

Advice? Questions? Comments?



Please reply soon!

Harry

Harry