Hi, recently me and my wife set up a new saltwater tank. Having read dozens of conflicting sources, I may or may not have made bad choices in setting up the tank. In any case, here goes: We have a 16gallon tank, with with I filled up with tap water (and used the water cleaning stuff that came with the tank), and have crushed coral (cleaned w/ water) as the substrate (I wanted sand, wife listened to LFS advice and overruled) as well as in the filter. We have about 2.5 lbs of live rock. Before even putting fish in the tank we had this brown looking algae grow on the substrate as well as the live rock. After consulting with the LFS they said it would go away but we could put a cheaper fish in as well as a cleanup crew. In goes a damselfish, 5 snails, and 3 tiger conchs. They did great for about two days and then slowed down the cleaning greatly. Couple weeks later we add a clownfish and a camel shrimp. The fish themselves seem uncomfortable in the tank, sticking to one side opposite the current. After adding the clownfish the conchs died one by one, which the LFS stated was at the hands of the fish. At this point I decided to get a test kit, (bc after all, the LFS insisted we didn't need one *until* we started noticing stuff), and found NO3 to be high. Do not know whether this is due to the conchs having died or other reasons. Sorry for the wall of text, I hoped it would be better to be thorough.