Filter upgrade

I have a 37gal with the Eclipse3 hood. Filter and bio-wheel built into
the hood. Rated at 250GPH. I think it is less. Pump riser tube is on
the left side of the tank. 2 water outlets on the right side of the
tank from the filter and you can direct the flow in any direction. I
like the fact that the inlet and discharge are far apart.
The down side is the filter cartridge is small and the coarse blue
poly fiber wasn't doing the job. So I cut out the fiber media from the
plactic frame and replaced it with white floss and put it in a net
bag. This helped. Water is clearer. Then I purchased a coarse foam
media made for the AquaClear filters. Cut a slit in it and placed it
over the inlet of the riser tube in place of the plastic strainer. 69
cents for the foam. This acts as a pre filter and I hope a place for
bacteria to thrive.
I am thinking of adding more filtration before the tank is full of
fish. A canister might be overkill.
HOB power filters will not work with this hood.
I was thinking a sponge filter should do the trick.
Any thoughts or suggestions?

It is a new tank. Been out of the hobby for several years. First fish
on the 9th of June. Cycling right now with 6 Tiger Barbs. Put a
package of Aponogeton bulbs in at the same time so have 9 plants
growing.
Plan to put 5 or 6 Serpae tetras in next.
Would like to place a pair of dwarf cichlids in the tank too.

chasgood