Err... I allready know one problem you have that may or may not be related to this...
You shouldn't use tap water, you should use purified water. Tap water has impurities that may mess with the tank. I have a 12Ga and I had no problem so I'll tell you what I did, If you do what I did you should'nt have a problem.
I put
live sand into the tank, and mixed purified water with a salt solution called Reef Crystals.
I let it
acclimate for a week, then added
live rock.
I let it acclimate for another two weeks then I added Fish and coral and plants and all that good stuff.
You should let the aquarium sit and aclimate for about four to eight weeks, you can't expect it to be clear right away.
My tank was still hazy after 24 hours, you have to let it sit longer.
saltwater fish aren't easy to keep, its alot of work, and you HAVE to use Purified water in my opinion and I'm sure alot of people would say so too.