I have a 8-gallon Resun tank that came with its own filter pump (Resun SP-800) that stopped working over vacation. So I bought a new one, and this also does not pull up any water at all...and a third attempt with another pump of the same model also didn't work. I checked all tubes and parts for clogs, or holes or cracks, and could find no indication as to why the pumps all don't work. I also checked to make sure it wasn't a power supply problem, and checked with various outlets. Still nothing. Do these pumps just have a bad rep, or am I missing something...? Any suggestions on anything else I can do to get my tank working and comfortable again?