Why not both? One is designed for breaking down with bacteria and the other designed to physically remove solid waste.

I haven't used an undergravel filter for probably the last 10-15 years. I know the gravel bed can work as a bio filter, but after so long there got to be so much grunge under the plate of the UG and I wasn't quite sure if I needed to tear down the tank to remove the grunge (which I did and hated doing it)or just let it be. Seems like it could have been messing with water quality to leave it down there. So I don't use gravel anymore, I use sand, specifically Tahitian Moon Sand and you can't use a UG with sand. I don't have to worry about food particles getting stuck in sand like it does in gravel and I don't have to vacuum it like you do gravel. I would recommend using aquarium sand, and I would recommend a power filter with a biowheel. I have a prefilter and trickle filter, so I couldn't say who has the best HOT filter. I think any of the name brands would probably be fine. I've heard good and bad things about canister filters - some have said they are hard to clean. I used to use Aqua Clear hang-on, and it did a fine job. It used a sponge and had cartridges for charcoal and ammo rid, if you need it. It didn't have a biowheel tho, but I had it before biowheels were "invented". My vote is nix on the UG, and just use a good power filter - maybe 2, so if one bites the dust, you still have one working while your fixing/replacing the other.

Thanks to both for the responses.. I am looking at the Moon Sand, as well as pool and spa sand.
I used to spawn and raise discus...and I used only sponge filters at that time. Bare tank.
Filters have inproved since those days.
I have a 2200 gallon koi pond as well. Frozen in now at Zero degree outside...but water is open. I cover with poly sheeting over supports.
Regards.....Koiboi

Hi
If you're going for a landscaped planted tank as opposed to a few plants. Check into the net for ideas on the proper substrates and lighting. There are many theories on the proper way to set it up and manage it. Filtration is not nearly as important with plants as fish. You get to look at all the pretty pix as a bonus lol.
gary

Thanks Gary...Is this a special forum on aquatic plant setups? I wish to set up fish, and aquatic plants.
Where do I go to view your suggestions??
regards...KoiBoi