Got a 105 gallon tank that has a sump with a 400 gph pump. The gravel in the tank is about 5 mm and around 3 inches thick. I am thinking of putting an air pump powered UGF to serve as additional biological filtration. Would the UGF also pull dirt into the gravel and actually suck it up into the tubes and out into the water column in order for the water pump to get it or will the dirt just stay in the gravel ? My objective is to both have biological filtration and avoid the monthly cleaning of the gravel using a siphon. I do not wish to add another water pump due to the electricity cost.
Would a RUGF or the one made with PVC pipes work too using the return from the sump ? Would it not make the water dirty with particulates since its constantly blowing it up ?
Hello; I have used UGF off and on for many decades. My take is that the gravel will act as a place for beneficial bacteria to colonize with or without the UGF. The added flow thru the gravel caused by the UGF in operation should somewhat increase the biological filtration effect.
I also doubt that a UGF will eleminate the need to siphon the gravel from time to time. This has not been my experience at any rate. I have a tank currently running with a air powered UGF and still get detritus with a gravel vac. The flow is spread over a large area and is unlikely to be strong enough to pull significant "dirt" all the way thru the gravel bed. The smaller stuff and that which breaks down to small stuff will likely go thru given enough time. The larger stuff will stay in the gravel and an occasional gravel vac will still be needed.
Two things can help with the gravel . One is the addition of Malaysian Trumpet Snails (MTS) to the tank. These snails burrow thru the gravel finding anything of food value and slowly churning up the gravel. This helps with water quality and I feel that the MTS waste is much smaller and should heve a better chance to be pulled thru the gravel bed. IF you find snails acceptable, they are a benefit to most tanks.
Another beneficial thing in tanks is live rooted plants. They will convert some of the "dirt" (I call it detritus others call it mulm) into plant parts. I have broken down planted tanks with UGF,s to find numerious root hairs grown thru the slits in the UGF plate. Under the plate was usually quite clean.
While I have not tried a setup with a reverse flow UGF, I hope to some day. Comments on this and other forums make it seem worth trying.
When I started keeping tanks many decades ago many the common practices of today were not so common. When the concepts of regular water changes and using a gravel siphon made their way to me, it helped my tanks a lot. The affordable powered filters were also not common. I ran tank filters off of air pumps for many years. While I do not relish the gravel vac routine, it has made for keeping a tank setup viable for much longer periods of years.
This hobby has a history of individuals trying out things and passing on the good stuff to the rest of us. If you do find a way to get along without gravel vacs, please let us know how it works.
Good luck
