Several problems

[fishysmellin]

Today after only having my fish and 2 corals for 2 days I checked the ammonia and it was up to .5 ppm the nitrites were at 0 so I took both corals and the maroon clown back to the store so my tank can settle out without any unnecessary deaths. Right now I have stuff on my sand on some of my live rock that is brown and I am fairly sure that it is not diatoms. This stuff is on there pretty good. Does anyone have any advise?
Thanks

 

[fishysmellin]

I should add before anyone asks, I have a 29 gallon with 40#s of lr. It has been set up for 6 weeks cycling before I put anything in it. I also found a worm about 1" that was pink and purple with white hairs, is that a bristle worm, do I need to get rid of it and if so how?
Thanks again