My fish tank is cloudy and there are bubbles at the top formed by the filter... need advice.?

Ok, I have a 36 gallon fish tank with 2 small bala sharks and 2 small pictus catfish (not grown to full size yet)... i feed them brine shrimp, but the extract food gets cleaned out by the filter mostly. I started the tank up 3 days ago, and it was doing fine till just today. Within the last 30 hours i have run ph tests and put tablets to stabilize the correct ph levels. The ph is currently 7.0, and i have put 2 different types of water chemicals to try to keep the water non cloudy, but its not working. Just within the last 10 hours there has been bubbles forming at the top of the tank (coming from the filter)... is this all normal? I am thinking about getting an ammonia tester, and a couple 'sucker fish' to keep my tank cleaner. Any help or advice would be appreciated.