I used a reverse flow UGF setup for 25+ years until a month or so ago when I switched over to a HOB that actually does a really good job polishing the water without me having to fish around in the tank and fool with the powerhead. I used to run it through a cannister before sending it back under the gravel, then switched to a powerhead about 5 years ago. The cannister didn't add any value to anyone except the manufacturers. Anyway, I just pulled out the filter plates in preparation for setting up a better substrate for live plants. Amazing how little gunk got riled up. Just asked one of the big online plant shops about snails. Let's see if I can get clean plants.