Did a VERY short experiment (as it turned out): I turned off the UGF's for two days wondering if I'd see any effect.
Wow, did I! Discus are VERY messy eaters and feeding five times a day (young) covers the tank bottom in fine food and a lot of solid waste (all sizes on that.) Since I get home late, I clean the bottom by vacuuming only once a day but after two days, my sand substrate was turning a light brown color (or colour for the UK people) in a lot of places (very fine food and fish solid waste.) This does not occur at all with the UGF running. That unit keeps those fine particles from getting down into the substarte where they are difficult to remove. Not doing that again!
This overall experiment - reverse flow UGF's - is working exactly as I suspected it would. My tank substrate is far cleaner (stays very white) and the tank clean up is more effective. This has, as I posted before, reduced the tank's phosphates from a more typical 1 -2 ppm (with the algae scrubber) to just 0.5 ppm! That is a factor of four improvement.
This new filter setup has also, to date, prevented any BGA from developing - for me, that was a problem unless I did daily water changes of 50%; but then, when my tap nitrates were holding at 10 ppm (they have dropped to under 1 ppm of late), those water changes weren't helping my nitrates, just phosphates. So while BGA did not start, the fish were not in water anywhere as clean as proper for discus.
So, overall, an algae scrubber and reverse flow UGF (not operating as a bio-filter) can hold my phosphates and nitrates to well under 1 ppm even with my huge bioload in the 75 gal tank. Better still, I have reduced my water changes yet have, at the same time, dramacticly improved my water quality. Win/win for both me and the discus ... .
Last edited by Cermet; 02-27-2013 at 12:03 PM.
Knowledge is fun(damental)
A 75 gal with eight Discus, fake plants, and a lot of wood also with sand substrate. Clean up crew is down to just two Sterba's Corys. Filters: continuous new water flow; canister w/UV, in-tank algae scrubber!! Finally, junked the nitrate removal unit from hell.
For Fishless cycling:http://www.aquaticcommunity.com/aqua...ead.php?t=5640