Canister Filter Vacuum - Fail?

[ericatdallas]

Well, I tried to convert my Fluval 405 into a vacuum and the suction/flow was actually worse than a gravity siphon. So that defeats the purpose of having it.

Any ideas why? I emptied it of all the filter baskets so it was just an empty bin. It was going down 4-5ft and going back up about 3ft.

Any ideas what's restricting the flow? Just the canister's pump?

Maybe I'll just go back to the gravity siphon.

Even the MJ1200 pulled water faster...

[Dennis The Mennis]

I am thinking of doing the same thing. I would like to hear success and failure stories also. My thought is that increasing the tube size like traditional siphons might decrease its efficiency.

[ericatdallas]

I did notice that constricting the tube on the output helped. I'm not sure if it has anything to do with the drain (hence output) being at a different elevation leading the pump to output more than the input (causing problems so the pump at some points ran dry).

Even if you widen the hose, you're still restricted by the flow of the inlet. I am also considering using an external utility pump that I have, but I hear the ones I have (Quiet One) aren't very good outside the tank and I need it for other projects (trying not to buy stuff).

[chrisb01]

The propeller in the filter would restrict flow and get stuck from time to time due to debris, since the output in the filter, when used as a filter has no debris going through it, it is left back in the filter media.

As opposed to the regular siphon in which water runs freely through, no matter the debris. The siphon has no propeller or anything to slow the water flow in it.

[ericatdallas]

The propeller in the filter would restrict flow and get stuck from time to time due to debris, since the output in the filter, when used as a filter has no debris going through it, it is left back in the filter media.

As opposed to the regular siphon in which water runs freely through, no matter the debris. The siphon has no propeller or anything to slow the water flow in it.

Ahh, that's actually a really good point...

I kind of put the project to rest at the moment (real life and higher priority fish room projects).