Im using one right now on a 40B with my sunsun filter 
im running 1000 gph on that tank.
The filter is doing good keeping my Black water crystal clear look fresh make me want to drink it. HA! Every problem people was having with the filter seem to be fix. new o-ring on the red valve barb.
IMO the filter is a mini of the fx5, you can also cut the sponge to make it look like the Marineland Magnum 350, which will do 2x the work
im running 1000 gph on that tank.
The filter is doing good keeping my Black water crystal clear
look fresh make me want to drink it. HA! Every problem people was having with the filter seem to be fix. new o-ring on the red valve barb. IMO the filter is a mini of the fx5, you can also cut the sponge to make it look like the Marineland Magnum 350, which will do 2x the work
