RF U/G Filters

[Joshie]

Looking through old TFH magazines (late 60's early 70's) nearly every 2nd add is for a Reverse flo U/Gravel filter. they seemed to be all the rage back then. Looking through shops etc lately they're no longer around, everythings back to the old classic U/gravel filter. Anyone know what happened to them? not so effective or unhealthy?

Many thanks

[Ira]

I've thought about setting one up. Only bad thing I can think of is that you get less aeration. Get great amount of biofiltration without getting heaps of crap sucked into the UGF and getting stuck.

[Caryl]

I have heard a lot about them but never seen one actually in a tank (I don't think so anyway). Different ideas come and go all the time.

[KerryO]

I've got a brandnew Eheim 3540 Throughflow undergravel filter for sale if anyone is interested.

Retails for a hundred and something, will sell for 50.00 plus post.

Can email photos.

Cheers,

Kerry.

[john1]

Hi Joshy

Yes, they still exist. I have one. Hagen have 2 models. The Flugal 402 and the 802 I think. And they WORK. At the flick of a switch from normal flow to reverse flow.

John

[Joshie]

Many thanks every1 for such fast replies.

Ira: those thoughts were along the same lines of mine.

John: How do you find them? (And i don't mean you just open your eyes and they're there! ) I was thinking of making a filter base up and pushing the return flow from a w/d trickle filter back into the tank this way. Any recommendations or fore-seeable problems?

I haven't yet set up the trickle filter since the tank i intend to use to house it has no face glass yet.

[john1]

Hi Joshie

I personally find it very useful. But to be on the safe side, goto Hagen's site, and read their comments regarding a reversible powerhead.

But here is my humble opinion.

A normal u/g filter, powerhead or airdriven, collects the dirt in the gravel. The very fine one eventually goes below the plate. If you do have other filters, loike a cannister etc. it will also clean the water of suspended dirt. BUT, if you reverse the flow of the u/g powerhead, then dirty water will enter the riserstem, go down under the plate and pushes the CLEAN water up through the gravel. Any dirt in/on the gravel will be suspended in the tank and subsequently be collected by the cannister or other filter. You can change back to normal flow later on. You can also do that on a periodic cycle. Forward flow for a couple of weeks, then reverseflow for a couple of days. Simple. But still, don't forget to get Hagen's opinion also.

Lots of people don't believe what I say.

John

[Warren]

As John states, the water going to the RFUGF has to be clean or the gravel will get dirty just as quickly as it used too. I used to use UGF's before going planted only with my tanks (no UGF). I had a very similar setup to what you are describing. My trickle filter fed the RFUGF. I added additional mechanical filtration using Spa Pool filter cartridges to remove everything down to 15 microns. The UGF never needed cleaning for 3 years other than quickly moving the gravel vacuum cleaner over its surface. I never tried RFUGF without the 15 micron filter so don't know how long it will take the gravel to get dirty with no prefilter.