Undergravel jets

[Vicious Camel]

hi all,

Just after some thoughts re. UGJs. I have seen them mentioned and praised on a lot of other overseas forums yet they don't seem to be mentioned too much on any of the australian boards. They apparently keep the gravel spotless and remove the need for vacuuming (which can be hard with lots of rockwork) but i just can't picture how they could be that effective. So, if anyone has some used them and has some thoughts i'd be glad to hear them.

thanks in advance

VC

[novafishy]

what is an undergravel jet? is that like a powerhead that is connected to a few pipes in the gravel and pushes waste out?

[Vicious Camel]

Yeah, that sounds like the one. This is what i am talking about here

[r.d.m]

these seem to be a version of a system that was popular a few years ago - the reverse flow ug filter i ran a 6 foot marine tank with these, instead of the airifts or power heads i used two power filters full of floss with the outlets going down the airlift tubes(they need to be sealed fairly well)and the results were brilliant ,a pair of clownfish spawned so i reccomend this system the only important point is that you have some sort of mechaniclal pre-filter so the gravel bed doesnt block from underneath. having said all that things have moved along in recent years and an "all in one"trickle filter or a well maintained power filter takes a lot of beating

[Gigitt]

LOL... thats the article I was going to post!

It is not like a UGF (under gravel filter) in reverse. (you normally do this to re-oxygenate the dead spots in the gravel by back flushing the debris back into the water)

It is not a filter but a fixed water movement device.

It is more like a wave maker without the expense - and is used to force water movement in many direction so there are no stagnant or dead spots.

You build it so that the water movement is low to the gravel and not high like a normal powerhead wave maker.

By having the water movement low you keep the debris in constant motion so that the filter can capture the debris, and also dead spots under rocks are avoided.

[wui39]

I built and used one for about 6 months. I think my design wasn't quite right as One side was getting higher pressure than the other. Other than that it worked well till i needed the power head for something else. Haven't put it back to gether although the framework is still at the bottom of my tank.

[Mbuna]

they don't seem to be mentioned too much on any of the australian boards

Hi, it may be because a large percentage on the forums keep africans with sandy substrates such as coral sand, shell grit, sydney sand etc. and sand doesent go well with UGF.

just a thought

cheers

Harry

[Vicious Camel]

i think some people here may be getting a little mixed up with the difference between undergravel filters and undergravel jets. Just take a look at the link i gave earlier and you'll see what i mean by UGJs. As far as i imagine sand would be fine to use with UGJ and whilst the digging os some cichlids may cause the pipes to be exposed (ie. and look a little ugly) it should not effect how they work.

Wui39, so do you think they'd have been good to use if they were set up well from the start? I would imagine it would take a lot of pre-planning to set them up really well and would have to be done when first setting up the tank.

anymore thoughts?

[saudukar]

Reverse undergravel filters are excellent. But the downfall is that you need to push ALOT of water through under the undergravel plate and you need a good mechanical filteration device to capture the stuff coming out. Also the gravel density above the plate needs to be even so that the flow of water is even over the whole plate. With cichlids they tend to dig it up. Making easier water pathways for the flow of water.

I personally hate seeing large internal filters. It ruins the natural effect of the tank.

I use a undergravel filter in the normal fashion but attach a canister filters inlet pipe to the UG uplifts this keeps a large amount of water pulling from the UG uplift and then direct the outlet pipe along a spray bar to push water down through the UG plate.

It is less important this way to have even flow over the whole plate as any water under the plate is worth filtering

You can do this in reserse by putting the spray bar under the plate but pulling the water evenly above the plate is alot harder.

[BaZ]

Like Mr Camel said, he is not talking about filtration. These are water jets which appear from under the gravel, as a way of creating good circulation in your tank.

I reckon the only hassle would be the one already mentioned, which is the constant digging of cichlids. A network of exposed pipes might not the the look you are after

[wui39]

I made the mistake of putting them in after I had already got my tank setup. It was a bit of a hassle but I suppose when they were working they did an adequate job. I'm planning to redesign and get mine working again soon. A little thing that I learnt while doing it, you don't have to use conduit benders. I used garden irrigation t pieces and L's and they seemed to work well.