Ok, I know the title is vague, but bear with me.

Ok so, it all started with the down fall of the led light system we had. We bought the leds to replace power compacts. The leds worked great for the first few weeks. Then one by one they dimmed or went out. After the third time going out, we opted to get store credit because we got a nasty algae bloom from the poor lighting. With the algae bloom, came the down fall. I'm not sure of the parameters, but 10 gallon water changes were preformed every week on the sixty gallon. Even with that, no progress, that led me to believe that the lights were to blame.

So, t5 were implemented and nothing changes. Lost all fish(blue tang, two blue chromis, two pajama cardinals) also all corals except a rose anemone, two pom pom xenia and a neon sinularia. So yesterday (12/18/12) I decided to take everything out for a fresh cleaning, only to find that I only have 5 gallons of r/o. No biggie, I'll leave corals in tub till tomorrow(right?).

I was going to ask someone to take my corals in till everything got better, but since I haven't been on in a while, thought it'd be inappropriate. Until now, I just got home, was going to do water change on tub for corals to find this nasty looking thing.

Two questions:
1. Is ok to keep, two tiger cucumbers, 1 coco worm, rose anemone, and 2 xenia in tub together in ~1 gallon tub till morning?
2. What is this?