Will An Undegravel Filter Have Any Impact Or Interfere With An Existin

[fishwarrior]

I currently have a sump setup with overflow and seachem matrix as my filter media (4 liters) on a 75 gallon tank.  In addition, I'm setting up an undergravel filter, more like an undergravel filter on steroids.  I understand people use UG as a filter, I plan on using it more as a maintenance tool to remove debris.  I had sand for a long time, never cared for it, it's actually a PITA to vaccum.  I like rocks anyway, so I decided to do a UG and will eventually do a RFUG.  Intially, I want to play with it using airstones and eventually use poweheads and hob filter with it.  Basically familiarize myself with how this works.
 
My understanding is the airstones will pull water down through the gravel, but what happens to the debris?  Does it get sucked up through the tubes and to the water column?
 
Since the UG will no doubt turn into some kind of biological, will it have any effect on my existing sump?  I would prefer the bacteria stay in the sump, just wasn't sure if this UG will get the buggers to gravatate into the DT.
 
Ultimately the goal is to reverse flow and/or figure a way to remove the debris via hob or powerhead with mechancial media.

 

[Lunar Jetman]

The standard undergravel filter won't throw the debris back into the tank, rather it is sucked into the gravel where it forms part of a bacterial filter within your gravel. Reversing this would kill off any bacterial filter and likely be dangerous if you did it after the standard UG filter was up and running, so if I were you and you wanted to run RFUG then I'd set that up from the beginning.
 
Also, I don't think any plants would like it very much since you're pushing any nutrients their roots would be trying to get up and away from them. If you don't have any plants then this won't really be an issue.
 
I guess depending on the strength of the device you choose to power the UGF with, you may find that your filters are in competition with each other but I suspect in reality they should both run together. Plenty of people run two filters so that shouldn't be too much of a problem.

 

[fishwarrior]

Luck would have it that the UG I bought since it was for a bigger tank, the tubes are too long and stick out of the tank.  I got the larger tank one because of a future plywood tank I'm building and figured since it came with three plates that would be better, didn't know the tubes would be longer.  I say luck because I was hesitant on getting an UG due to the many unfavorable reviews.   So I have to return the UG and rather than put myself through potential tourtue with a UG, I decided to make my own out of PVC and hook it up to powerheads and/or HOB filter.  At least then I can get modify it to fit my needs.

 
By the way, how comes there's no spellcheck on the post? I'm use to the mispelled words being highlighted so I can correct them.
update: I fixed the spellcheck.

 

[TwoTankAmin]

The key to an undergravel filter is not having big fast flow through it. You need a slower but steady flow through. And the bacteria will not care about your plan, they will live where conditions are best for them which will likely be the gravel.
 
A RUGF keeps solid wastes suspended in the water. They work super when combined with a second filter set up mostly for mechancal filtration to remove those solids.
 
If you set up the RUGF be sure to use prefilter sponges on the powerhead intakes.
 
Oh yes, you can plant with RUGFs, I did. However, they are not good for use in higher light planted tanks.