Zoas died off gradually POST-MORTEM

This is an earlier pic of them when they started dying. (Click pic for close-up). The ones in the foreground closed, got some flaky white crud on them, withered and died and then the others followed. The whitish infection spread progressively from one end of the frag base to the other. I tried dipping them in Furan-II daily for 3 or 4 days (for Zoa pox) but this did nothing to stop them from dying. Of 30 some polyps there are now two left. When basting them with a turkey baster some crud did come off of them and now I've put them right under a nozzle. I tried strong, moderate and low flow but the infection spread with slowing. All my chems are just fine. Post mortem? What killed them?!

 

It looks like a case of rtn, possibly caused by a bacterial infection. You can try and use airline tubing to siphon off the dead/necrotic tissue. Then, depending on the severity of the infection, you may decide to try giving the coral a bath with a Lugols Iodine solution like TM Pro Coral Cure or similar product. The iodine will act as an antiseptic and hopefully prevent the spread of the tissue necrosis.