I can only agree on that one! UGFs need to be vaccuumed completely at least once a week with the syphon, thoroughly, and even then there are always particles that get trapped UNDERNEATH those plates, and just sit there creating anerobic bacteria (bad bacteria) over time. Its a cheap solution, but not very good for goldies, since they produce an enormous load of waste.
For tropicals it might be fine, since those tiny little fish can not by any means mess up the tank that much...
I took out my UGF from my 160 gl tank, and I was very correct with the vaccuuming and such, but boy, what dirt was underneath!!! Bright me, thankfully took out the the fish beforehand! It took a full 2 hours before the water finally cleared up enough and the dirt settled down on the bottom for me to vaccuum it off. I forgot a tiny little Oto pleco in there, and couldnt see the poor thing in all the muck.
I have also noticed, when people complain about their water having a bad or strong fishy smell, its usually those goldie keepers with UGFs....
If you still can, exchange that thing for a hang-on filter. So much easier to take care off!