Reverse Undergravel Filtration
- Thread starter Don424
- Start date
It is fine for freshwater, since FW tank is pretty much sterile. But for saltwater with rock on the top, it is pretty difficult to make sure the substrate is clean all the time. If you have the time to gravel-vac it every once a while, then it may be worthwhile to setup this way just to be different and be able to use the UGF that has been sitting around in the garage for years. But IMO, there are many other setup that is superior than RUGF setup.
I might have spell it incorrectly.
Basically, it is a plate with macroalgea growing on it. Once a while, the algea is removed manually as a mean of nutrient export. Many people keep Caulerpa and other macroalgea in the sump/refugium, and by removing them periodically, it serves the same purpose.
Basically, it is a plate with macroalgea growing on it. Once a while, the algea is removed manually as a mean of nutrient export. Many people keep Caulerpa and other macroalgea in the sump/refugium, and by removing them periodically, it serves the same purpose.
Don424":3bp61d7f said:Is anyone on this board using reverse undergravel filtration?.....crushed coral or a combo of crushed coral and puka shell is the substrate used.
I'd like to hear feedback from anyone on this type of system even if you're not using it.
Thanks
I think your understanding of a reverse undergravel filter is correct. It is reverse because the water flows from the bottom of the substrait to the top then up to the tubes and is pumped back down. The idea is the "crud" is broken down under the substraight instead of on top and therefore outta sight. I have heard many good things about reverse undergravel filters but have no experience. My "gut feel" agrees with others that decorative or live rocks on top of the filter would interfer with its operation. One advantage is that water changes by draining from the "down draft" tubes would back flush the filter.
I don't use one because I like being able to rinse the filter media without tearing down the entire tank. But then I had a (forward) undergravel filter running in a simple fo system for years and years. So I see no reason why a reverse wouldn't work.
Fatal Morgana":1lrfuskq said:
I don't know what you mean by sterile but it was full of algae and had a bunch of pods in there. Also a dead coral for decoration, and dolomite substrait. Did have some fish spawn in there so they must have been happy.
And of course it was not a reef tank and I now prefer to not use an undergravel filter. But it did seem to work in that simpe system.
I heard on another board a poster had to be away for 6 months. He told told his wife to replace the water that evaporates and feed the fish. 6 months later the tank and substrait was still totally clean. Was probably a FO tank though. And that was a reverse flow filter also. So I guess they can work. I just don't like the idea of not being able to clean or change the filter media without tearing down the entire system is all.
The idea behind the reverse UGF was to improve on a few issues with traditional undergravel filters. In theory, the RUGF should be better than a regular UGF for a few reasons:
1. The RUGF shouldn't clog with detritus as quickly because it doesn't use the substrate like a big mechanical filter as a traditional UGF does. Of course, for this to work you have to prefilter the water being pumped under the plate (ie. feed it with a canister filter or powerhead w/intake filter).
2. There should be less substrate compaction and thereby dead spots and channeling of flow through the substrate over a given time period because of the bottom-to-top flow.
3. Placing rock/decor on top of the sandbed should have less impact on the flow through the RUGF since it's coming from beneath this stuff instead of trying to pull around and under.
All that said, I would never use a UGF again, regardless of which way it is flowing.
1. The RUGF shouldn't clog with detritus as quickly because it doesn't use the substrate like a big mechanical filter as a traditional UGF does. Of course, for this to work you have to prefilter the water being pumped under the plate (ie. feed it with a canister filter or powerhead w/intake filter).
2. There should be less substrate compaction and thereby dead spots and channeling of flow through the substrate over a given time period because of the bottom-to-top flow.
3. Placing rock/decor on top of the sandbed should have less impact on the flow through the RUGF since it's coming from beneath this stuff instead of trying to pull around and under.
All that said, I would never use a UGF again, regardless of which way it is flowing.
ChrisRD":u187j72e said:The idea behind the reverse UGF was to improve on a few issues with traditional undergravel filters. In theory, the RUGF should be better than a regular UGF for a few reasons:
1. The RUGF shouldn't clog with detritus as quickly because it doesn't use the substrate like a big mechanical filter as a traditional UGF does. Of course, for this to work you have to prefilter the water being pumped under the plate (ie. feed it with a canister filter or powerhead w/intake filter).
2. There should be less substrate compaction and thereby dead spots and channeling of flow through the substrate over a given time period because of the bottom-to-top flow.
3. Placing rock/decor on top of the sandbed should have less impact on the flow through the RUGF since it's coming from beneath this stuff instead of trying to pull around and under.
All that said, I would never use a UGF again, regardless of which way it is flowing.
Well said, and I agree - especially with the last statment. :wink:
Just that I replaced the powerheads on my dad's pathetically neglected 72g FW tank to try running the UGF in reverse.. The Hagen/Aquaclear powerheads are absolute garbage for running in reverse, despite the advertising on the box.
I don't know what's coming out of them, but it's definitely less than 1/4 what normal flow gives.
I don't know what's coming out of them, but it's definitely less than 1/4 what normal flow gives.
Sharkky":2ecfzemk said:K":2ecfzemk said:Just to say that I have had a standard UG Filter running for 3 and a half years now with no problem. The tank is fish only but it is pretty heavily stocked with messy feeders.
Mmmmm, would love to see what's under those UG plates! 8O
Nice image. I don't want breakfast anymore
. When I used to run a UG, for both fresh and saltwater (years and years ago) every month I'd stick a power head with tubing attached to it on reverse and suck gunk out from under the plate through the lift tube as part of a water change. Ewwww.Sponsor Reefs
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