Fluval 405 canister filter

[trigger11]

I just purchased a Fluval 405 canister filter in the hopes it could help me with a filtration issue I am having. I will be having a pretty major surgery coming up and wanted to get something that didnt require too much maintenance. My plan was to install it under my tank and install it to go into my sump. After I get it put most of the way together I read in the instructions that it says it needs to be below the tank. Where I want to install it the top of the canister would be a few inches above the water level. Does anyone know if this is an absolute requirement?
Any ideas would be appreciated.

 

[yerboy]

the filter needs to be below the water level in the tank or sump because it works by being gravity feed. It will not suck water up.
However i see no reason you cant install a 2nd pump on the return line to suck water from the canister and pump it into the sump if you wish. And that would essentially suck water from the sump into the filter.