I started using a Python recently and I don't seem to be having much luck with suction. The first time I used it, the suction was very weak, enough to slowly change and fill the water, but not strong enough to pick anything up from the substrate. The last time I used it, it pretty much had no suction at all. I could use it to fill the tank back up, but even that was pretty slow. This isn't a DIY, it's an actual Python I got as a gift. My husband even totally replaced our faucet to one that was compatible. I've tried the obvious, checking tightness of connections, etc. What in the world am I doing wrong? Thanks for your help.