Good morning fellow reefers , so I Have run into a bit of a pickle and wanted to see if anyone has an idea on what can be happening , I started the tank about 7 months ago , I have 15 g fusion aio tank with ai blade grow , mightyjet 326 returned pump , I'm running filter floss ,marine pure media balls and chemipure blue. I had a big crash like 2 months ago because I had bacteria bloom and I had a BTA and it perished and nuke the tank but I caught it early only had 2 clowns that did perished also had a duncan, 2 small zoa colony , gsp , kenya tree and pulsing xenia everything made it well duncan did suffer hasn't open up fully, well I did a 90% change and did another 90% in a period of one month when the coral opened up ( except the duncan ) I went and got a pair of clownfish everything was fine for a month until I added a 6 line wrasse this weekend everything looked fine no aggression but two days after I woke up to every one dead water quality is ammonia 0 , nitrite 0 , nitrate 0 , phos 0.5 salt 1.026 temp 77f . Any thoughts on the matter ?