Help! Elegance Coral issue

[Viatorem]

So I have this elegance coral, and I don't know if it's an aussie or indo. It had been doing fine for a few weeks, huge and expansive, but the past few days it'll puff up with shrunken tentacles, and then suck back in. It's been sucked in like this for about 2 days now (see pic) and there's a lot of a mucus-esque substance. 

 

Tank is relatively young, up and running for 3 months. 

Nitrate - 5-10 ppm

Ph - 8.1-8.3

Ammonia - 0

Nitrite - 0

LFS says my alkalinity is high, and my phosphates are high as well (seen by sludge on substrate)

 

Any help, opinions, tips, suggestions are EXTREMELY welcome and needed!

By high alk, he said i was at 15 and should shoot for 12

[Tamberav]

how is your alk 15? Do you dose? I can't imagine any salt mix being 15. You should never dose without testing. Most people here aim for natural sea water which is 7-8!

 

If you don't dose, I would question their test kits. What salt mix do you use? What size tank? What fish/coral do you have?

 

I would buy your own alk kit, low range phosphate kit (hanna). I am not sure what your LFS used but it has to be a low range kit to be accurate. These tests will come in handy as you progress through your tank. 

 

To start, this tank probably needs some water changes and cleaning (turkey blast rocks, siphon sand, ect) to get phosphate under control and alk down. 

 

An Iodine dip may also be warranted to prevent infections. 

[Clown79]

Elegance corals can be difficult to keep as they often suffer from a disease that only effects them.

 

I agree, you should do your own testing because lfs is not reliable and certain tests need to be done frequently during times of tank issues.

 

The sludge on your sand looks like cyano.

 

We need more info regarding filtration and maintenance routine to better aid you.