Under Gravel for waste

[Gobrian44]

I have been thinking about this a lot and am about ready to set it up. I want a bare bottom tank with an under gravel filter with a high flow rate some where between 10-20x an hour so that is the bottom stays nice and clean. But this would only be mechanical. I plan on having other HOBs for biological and chemical filtration.

SO:
what would i use to draw the water from the UGF to a possible sump tank. I was thinking a pump like a GEN-X PXC link. But would i place that in the sump or what and then would i need a submersible pump in the sump to pump it back to the tank.

This may be very confusing. But i'm tryin to make sense of it thanks!

 

[dawnmarie]

This is very comfusing.
You want "a bare bottom tank with an under gravel filter" ?
Does bare bottom mean no gravel ?
A UGF, with gravel, won't stay clean without regular gravel vacs.
It feels illogical to have a UGF, HOB's and a sump all at once.
The closest I can come to making sense of this is using a DIY overflow attached to a UGF plate/riser assembly to collect waste off the bottom ?
Or, you could connect the suction from the HOB to the riser on the UGF assy.
It might work, although you wouldn't have a "bare bottom".
Seems a little "Rube Goldberg" to me.
I'm not saying you have a bad idea, but, you might want to think this through a little more.

 

[Toby_H]

I would either say A) you didn't explain your idea well enough, or B) you idea has a few holes in it... I can't tell which it is...

I wouldn't consider it a "bare bottom" tank if the bottom fo the tank has a UGF on it... with or without substrate... So you seem to be talking about a tank with UGF and no substrate...

If you set up a UGF with no substrate, all fo the water will enter the riser tubes very near the rise tubes and there will be no flow at all on the far side of the tank from the riser tubes. The gravel is needed to force water to be collected somewhat evenly across the entire bottom fo the tank. In other words a UGF with no G (gravel) doesn't work properly...

Also, the gravel is the media with a UGF, so if you do run it without gravel you are running it without media. So any waste it sucks up it will just push right back into the water column...

But I guess this is why you aer thinking about plumbing it into a sump... It is possible to plumb your sump so the water is drawn in from the bottom of the tank... but it requires a few precautions. bypassing these precautions can allow a siphon to form and drain the tank when the pump is turned off. Any sump should be designed so the pump can be turned off without ill results.


Bare bottomed tanks are quite easy to keep waste/debris free. Slap a powerhead low in one corner pushing across the bottom and valla, you've done it. In larger tanks put a power head in each rear corner and the same is acheived.

It sounds to me like you are combining many different approaches that are not meant to be combined... thus you are reducing the practicality and efficiency of each...


...unless I misunderstood your overall approach...

 

[Gobrian44]

OKay i would like to have a UGF to control the physical waste in the system and then the overflow to filter and clean the water. So in short the UGF would clean the tank of visual debris while the overflow would then clean the water for ammonia and nitrites and nitrates. Make sense now. Sorry for the confusion

 

[Gobrian44]

I meant barebottom in the sense that there is no gravel or sand. Just a UGF

 

[Toby_H]

SO essentially...

You will be using UGF plates as the intake for your sump...


If that is correct, the first problem I see is distribution. A UGF plate without gravel on it... will suck all of the water from right around the riser tube... and will suck absolutely no water from the far side of the plate.

For example, if you have a 2' x 2' UGF plaet... with a riser tube installed in the bottom left corner... Every inch you get away from that riser tube the flow rate would drop considerably... By the time you are 4~6" away there will be no flow rate worth considering. I'm not saying it will be a dead spot, but it wouldn't be measurable "flow rate". Now start moving 14", 16" or 18" away and you might not have any water movement from the riser tube... much less enough to keep the bottom free of debris.


For a UGF to work properly, you need gravel.

 

[Gobrian44]

what if i had under gravel jets pushing everything toward toward the riser tube. For instance

4 foot but 2 foot UGF. With the riser tube dead center in the back at 2 feet. Then i had a spray bar on each side of the tank propelling the waste toward the riser tube. would that work better?

This is mainly because i hate watching the poop just float around the tank. So i'm devising a way to eliminate it.

Thanks!

 

[Toby_H]

what if i had under gravel jets pushing everything toward toward the riser tube.

That would work... but it's removing the purpose of the UGF...

So why not ditch the UGF al together... use powerheads (I suggest Hydor Koralia) to push the waste along the bare bottom floor into a corner... then use a well designed overflow intake that is capable of removing waste from the bottom of the tank...

Plus with the UGF and no substrate you would have a real cheesy looking piece of plastic covering the entire bottom fo the tank which would look horrible in my eyes.

 

[Gobrian44]

true. So what kind of media as far as PPI foam should i use? my reason for this whole thing was because of the pain in the butt of my canister losing power due to clogged bads. what would u recomend?

 

[dawnmarie]

Is this on the 70 gallon tank in your sig. line ? 24 x 48 x 14 ?
What canister and pads etc. are you currently using ?
How often do you perform filter service ?