Hi and welcome to the forum!
Since no one has answered your question yet I'll give you my opinion. I wouldn't use an ugf myself. It isn't good for much in my book. It will be ok for a while but you have to maintain it...and maintaining it means keeping all the poop vaccuumed out of the gravel so that it doesn't accumulate and become clogged and all nasty. Eventually even though you keep the poop vaccuumed up on a regular basis you are still going to have to eventually take all the gravel out and the filter and clean them of buildup that escaped your vaccuuming.
It is also not a good filter for a planted tank if you ever want some plants down the road.
If I were you I would go ahead, save myself the trouble down the road, and convert to sand. Its much easier to maintain, looks nicer, and your fish will absolutely love it, especially your bottom feeders. I've been using sand for years now and I couldn't imagine using gravel with bottom feeders anymore. I would feel very sorry for them if I did.
Also IMO the AQ filters are just as good if not better than any biowheel filter. I have an Emperor 400 and while its an excellent filter (aside from the noise it makes), the biowheels can still only go so far. They are not adequate for a heavily stocked tank IMO. I think they're a little too overrated. The washable sponges that are made for AQ filters (washing with old tank water, of course, not chlorinated which would kill the good bacteria) are the best choice for mechanical and biological filtration and 1 or 2 filters with 1 or 2 sponges each would be more than enough.
HTH
David
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