tank is crashing!!!

[hawaiiguy]

I've got multiple problems going on in my tank right now. All of these symptoms began over the past week or so...

First, my bicolour angel stopped being active and now she sits at the back of the tank and her fins are deteriorating fast.

Then, I noticed the start of a dark red slime on the substrate (probably cyano) that has spread to cover half the tank over the past two days.

My zoanthid colonies will not open up (they havent been open for about 3 days now)

My mushroom corals are "shriveled" and they won't spread themselves out.

My LTA looks ok, but its tentacles are "corkscrew shape", not extended like normal.

Now, this morning about half my corraline algae is white!! It happened over night!

My ammonia and nitrates are almost undetectable. I'm not sure about phosphates though, currently I don't have a test kit for it.

The strange thing is that my leather coral is doing great! I would've thought it was more sensitive than zoos.

Can anyone help?