Has any one tried this ? expensive trial but may be worth it fit the old school under gravel filters but have bulk head fittings that would pull the waste collected by the under gravel to a gravity fed built head down to the sump filter ?

I have 3x inch holes in the back of my tank 2 supply return water to 3ft bio filter the third is the return pump after filtration and works a treat
as most waste is bottom bound under ground filters would be the answer so keeping them clean maybe apart from leakage a 1 inch hole below gravel level drawing waste to the sump filter I think it would work
cheers Gazza

My experience with under gravel filters has not been good...very messy if you want to remove it for any reason and an external canister filter will work better and more efficiently every time.

the problem you will have with any cichlid is they dig everything up. that will include your under gravel filter. my thoughts are oscars are far too messy and you will end up with a lot of crap and food sitting in your gravel.

I have actually been wanting to try this. I want to hook up my canister filter input tubes to the tubes on the undergravel filter. I've read somewhere else about someone who has done this who says it makes gravel cleanings almost non-existant. Haven't actually done it yet. Sounds good in theory.

The problems with UGF's is that the gravel gets blocked with waste, I think 'pulling' the waste through the gavel wont work, the gravel will still block up.

The solution is to have the water flowing the other way up through the gravel. I take the output of a cannister and push the flow down the uplift tube and up throught the gravel. I rarely need to do a gravel clean. The gravel is never spotlessly clean but it never gets really dirty. I only do this to reduce gravel clean, not to add any extra filtration. Any extra filtration is a bonus

The other problem with UGF's and oscars is, as marcus says, oscars dig. If they dig down to the gravel plate then the UGF wont work. To combat this put an inch of gravel over the UGF plate, then add a gravel tidy and then add more gravel. A gravel tidy is a sheet with holes in it

Yeah my old O Slarti used to rearrange his tank on a daily basis
thanks for the input though guys was just a brain fart I had

Cheers Gazza