A RUGF creates an atmosphere where pods, worms, tube worms, bacteria and Godzilla larvae can live and reproduce all the way through the gravel and especially in the detritus laden area under the filter plate. That is a place absolutely filled with pods and worms which I can see through the bottom glass. But it depends on what you want to keep. I have breeding mandarins, 2 pairs of pipe fish and 5 or 6 queen anthias along with a few other creatures that rely on pods and worms. If you keep a tank full of moray eels, lionfish and manta rays you don't need this microcosm of miniature food sources. I personally run a very natural tank and don't use almost any of the things written about in this thread.
For many years my nitrates were under 10. Now they are 160 (as tested by a LFS because I don't have or want test kits)
My phosphate is 2.0. I don't care what the readings are because I believe most of this hobby is run on rumors. If nitrate and phosphate caused algae, I would be able to open up a produce stand in front of my tank.
But I have no algae.
Corals supposedly don't like high nitrates. I keep mostly a LPS, gorgonians, sponges and softy tank but I do have a few SPS that have quadrupled in size and have had many grow to large. (Those all croaked in an accident when my Supermodel tank sitter let the water level fall 7")
My nitrates are considered high because I keep my fish healthy which means spawning. To do that, you must feed way to much for a tank full of SPS which I am not striving for. I also use no dry foods.
I also think all this talk of trace elements is silly except if you are going for "no" water changes at all. I only change about 20% of my tank 4 or 5 times a year and only dose baking soda and drive way ice melter.
My tank runs fine and has no problems even after decades so maybe a Reverse Undergravel filter is needed to keep a tank this long, no one really knows. :D