I have a 75 gallon tank with a sun sun 304b filter on it. I took it through a 4 week fishless cycle. Everything looked great, so I went out and got my first three fish. A red tail shark and two dwarf gourami. Within 24 hours the shark and one gourami were dead and the last gourami seems to be on his last moments. I quickly took him out and put him in a bucket while I did a 90% water change. I notice that he look much better in bucket so I left him there over night. He looked great the next morning so I put him back in. By lunch time he was on death's door again. I started looking at my tank and his swimming pattern and I am wondering if the strong current in the tank is my problem. I am using the spray bar that came with the filter. Water just shoots straight across the tank. Could that be killing the fish that fast? How would you slow the current down? It came with no instructions, so I am clueless. Am I on the right track? Or is it something in my water? I have sand under gravel, a piece of driftwood, an hydro bubbler, and two terra cotta pots that I coated with 100% silicone and sand. Yes, it was the 100%. I followed all of the advice I found here. Thanks in advance!