I have a syphon and it doesn't do the job like I want. I want more pick up with out sucking up all the gravel like a wet/dry vac would. When I was a kid my dad had a powered tank vac that did the job filtered out the crap and pumped clean water back into the tank. Bc it pumped water so fast it would pump the smaller tanks empty before the tank was clean. That's been 15 or 20 years ago. I asked him about it he said he doesn't remember what it was called. Maybe it was just a canister filter set up like a vac but that's not how I remember it.