andspencer11

I am getting a 55g tank in the next couple of days. I have read a few comments about not needing as much flow as say a power filter. Is it due to the efficiency? I have been looking at the Rena XP2 but it only has a flow rate of 300gph, but it is "meant" for a 75 gallon tank.

mathas

From what I've heard, the reason for needing less flow from a canister than from a power/hang-on-back filter has to do with how water flows through them.

Some of the water in an HOB filter can bypass the media entirely, which means some of the water coming out of the filter hasn't been filtered. Canister filters, on the other hand, force water through the media by their design, meaning you have to flow less water through for the same amount of filtration.

Hopefully someone can confirm or correct this.

That said, I think an XP2 would be fine for a 55g.

clinton1621

You should have at least 10 times your gallons as a flow rate... so you need a flow rate of at least 550gph for a 55, in my opinion you need a bigger canister or a hang on filter added with it to make up the difference (ex. a hang on with a 250gph flow rate plus the 300gph canister)

Im not necessarily saying the canister wont work by itself (they do filter out way more than hang ons) but canisters also have less oxygen exchange because they are enclosed and sealed, which means less bacteria