siphon question

[Gazingatstars12]

I got one of those nifty water changers that goes on the faucet. It works good but I can't seem to get a strong enough siphon so suck up the debris in the gravel. I can see it floating around in the tube but I dont think I am getting much through the hose.
The tube is very big... about a 2.5 inch diameter.
Would a smaller vacuum tube work better?
Or is there some trick with the faucet I'm missing?

 

[Rutrag]

Make sure all your fittigns are tight. If air is getting in anywhere, you'll lose suction. Also be sure the hose isn't kinked or being crushed anywhere.

Beyond that, you may not have enough pressure to create good suction. I have a faucet in my house where it works very well, and another where it doesn't.

Sometimes I just open a window and start a siphon without the it being on the faucet to save water anyway.

 

[Gazingatstars12]

So the faster I'm running the water the more suction?

I think that's where I went wrong

 

[Rutrag]

Yes. The "pump" attached to the faucet is a Venturi. As water rushes straight down, it creates a suction through the piece the hose attaches to. The more water going through, the more suction.