Reverse flow or normal flow?

homerr · Mar 29, 2004

I'm not exactly a 'Noob' to the aquarium world, but it's been a long time since I've had one up and running, so I hope this forum is the right place for my questions.

I'm a big fan of under-gravel filters, and that' all I'll use.
I was reading about the 'reverse flow power head' and the fact that they are much better than the normal flow.
I got an Auquaclear 402 power head that has the reverse capability. (The 402 is a bit large for a 20 gallon tank under normal flow, but I got a good buy on it

)

My questions are:

Under normal flow, the pump really pushes the water around (duh.. it's twice the size it needs to be).. However, under reverse flow, it doesn't seem to move a lot of water, or at least I can't tell.

1. Is the 402 big enough for a reverse flow application in a 20 gallon tank? Is the reduced water movement normal under reverse flow?

2. I have two under-gravel filter plates with only 1 power-head attached to one plate. (The knock-outs have been removed from the plates) Should I put another riser on the other plate, or is the power head enough?

Thanks for your time.

~ More questions than a 2-year old! ~

H.

OrionGirl · Mar 29, 2004

The 402 should be plenty for that sized tank. The slower flow is normal with powerheads in reverse operation, and is not really a problem. I can't really help you on the other plate--I'd probably want them both running in my tank, but that's just me.

A point of warning--if this tank has been running UGF for a while, you are going to want to do some serious cleaning of the gravel and under the plates before converting. You'll be shocked at the amount of 'stuff' that comes up. I'd urge you to have some sort of mechanical filter available to capture the solids that will come up.

homerr · Mar 29, 2004

Thanks for the reply...

I just set the tank up, so it's clean.
I just wanted to make sure the 402 is powerful enough on it's own to filter.

Under normal flow, it really moves the water, and the fish have to run for cover becasue of the current the 402 produces!

I thought about putting another reverse flow head on the other side, but that would definatley be over-kill!

H.

daveedka · Mar 29, 2004

Reverse flow creates very little "felt" current on the tank, one of the advantages. If your gravel isn't bouncing, it probably isn't too much, I am not familiar with the knock-outs, I have yet to run 2 plates on one powerhead, but I am sure you will be fine if the powerhead is that much oversized.

RTR · Mar 30, 2004

I do hope that you are pre-filtering the powerhead - that is the only way RFUG works for any length of time.

DEmigh · Mar 30, 2004

I have the same brand/model powerhead as you, and have, in the past used it in reverse flow mode.

I agree with RTR that pre-filtering the intake is very important.

I suggest a cylinder of open foam at least two inches in diameter and about twice that long. You can cut a notch in the center of one of the circular ends so that it will fit over the nozzle.

The great thing about an improvised filter like that is that it's extraordinarily easy to clean. Since the gravel on the UG plate(s) is the repository for the nitrifying bacteria, you can just rinse the pre-filter with warm tap-water, squeeze it dry, and slip it back on.

homerr · Mar 30, 2004

DEmigh,

So where would you place the foam on the 402?
The 402 doesn't take the water in at it's normal output in reverse flow. I think it draws the water from around it's base?

Would you put that foam filter on the cone that goes into your riser tube?

And lastly, where would I get that type of foam. THere are so many types out there. What are some ideas of the type of foam?

Thanks,

H.

daveedka · Mar 30, 2004

I am not largely familliar with the Aquaclear powerheads. If it requires a DIY type filter, I usually buy AC 500 sponges and adjust them to fit. The major drawback is you can see a yellow sponge from 17 miles away in a fish tank. I use the penguin reverse flow kits for many things. this is basically a 6" long black round (probably 2.5-3" dia.) sponge with a hole through it. If you buy the full kit it comes with a ceter tub to support the sponge, but it doesn't sound like you can use that. I am also going to buy some of Big Als universal sponges as soon as I can get an answer on what color they are.

RTR · Mar 30, 2004

I use 402s and 802s, but never reversed as they are so inefficient that way.

Like daveedka, I use Penguins with their reverse-flow kit for RFUG. Vertical black sponges are less obtrusive to start and much easier to conceal.

homerr · Mar 30, 2004

I went down and got a Penguin 660R kit. It comes with the whole mess to run in reverse.

It's a 170 GPH, so I think it's big enough for the 20 gallon.

I've heard and read a lot on the reverse flow... I have to give it a try. What the heck!

Thanks for your help!

H.


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Reverse flow or normal flow?

homerr

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OrionGirl

No freelancing!

homerr

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daveedka

Purple is the color of Royalty

RTR

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DEmigh

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homerr

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daveedka

Purple is the color of Royalty

RTR

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homerr

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