# Help making undergravel jet system



## DavidH (Mar 11, 2011)

Some of you may have seen my other posts... I'm in the process of putting together my 90 gallon tank (going Mbuna)... anyway, I figured tossing one of these in couldn't hurt, and now, before there's anything in the tank, would be the best time to do it. Just looking for some help with design.

Today I picked up some clear plastic tubing (about 20' of it) and more fittings than I know what to do with (elbows for the corners, T's for the jets, straight couplers just in case). I ultimately don't want to spend too much on this part of the project, so I only planned on using a couple of powerheads as my pumps for this (no fancy and expensive special submersible pumps)

I'm going to build around the egg crate... tank is 48"x18".

My idea was to split the crate in half, and have two halves... each as its own closed loop with its own powerhead. I figured then I could have one jet for each side in the middle (one toward the front and one toward the rear) - this is clearly getting a little complicated to explain - and probably just as much to understand my crappy explanation, so here's a crappy drawing to help.










The two squares inside the tank could be looked at as the two pieces of egg crate or the tubing itself (each piece of eggcrate would have plastic tubing all the way around). Either way would be accurate.

The huge circles are there just to give an idea of where I would have my rock piles, not that it would make a huge difference.

Anyway, that's just what I had in mind... I'd like to hear your ideas on how well this would work and if there are too many jets somewhere or not enough somewhere else...

I wasn't sure if I should have any on the rear, since that's where my powerhead and filter (canister and HOB) inlets/outlets would be...does it need 4 jets total (2 on each side) on the front?

I understand the idea behind the jets (avoiding dead spots, maintaining currents, keeping debris off the bottom, etc.), I'm just not sure what the best way to implement it is.

Again, I haven't done a thing yet but buy egg crate, tubing, and fittings, so suggest away.


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## BigDaddyK (Nov 6, 2006)

I can't see a picture here.. I am getting to the point of planning UGJ's too. I'll be following this thread as well!


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## DavidH (Mar 11, 2011)

Darn! Let me try a different host.

Should be fixed now.


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## jason081180 (May 5, 2007)

i would look at this thread http://www.cichlid-forum.com/phpBB/viewtopic.php?t=208104&postdays=0&postorder=asc&&start=0

i did mine like this. you can see my plans for my 75 gal that is now going to be a 90gal. either way they have the same footprint so the same design. i used 1/2 PVC for mine and you need at about 100GPH per Jet so you would need 2 powerheads doing 400GPh for your plan.


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## DavidH (Mar 11, 2011)

jason081180 said:


> i would look at this thread http://www.cichlid-forum.com/phpBB/viewtopic.php?t=208104&postdays=0&postorder=asc&&start=0
> 
> i did mine like this. you can see my plans for my 75 gal that is now going to be a 90gal. either way they have the same footprint so the same design. i used 1/2 PVC for mine and you need at about 100GPH per Jet so you would need 2 powerheads doing 400GPh for your plan.


Thanks, man. This is perfect!


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## DavidH (Mar 11, 2011)

OK, so I'm having issues.

I'm loosely following the thread posted above... main difference is i'm using clear 1/2" tubing, not the rigid pipe pieces.

I wanted to follow this diagram, from that post










the one exeption would've been that I don't have two canisters... my second filter is a HOB, and the intake is in the middle of the unit so I can't have it exactly in the corner.

That aside, the real issue I'm having is that the tubing comes up higher than the egg crate... and even if I didn't have the egg crate, the problem would actually be worse, because the tubing would be even further from being flush with the bottom. I don't want to run two tubes down the middle of both halves of the tank because that severely boxes me in in terms of rockscaping... and I plan on having rocks throughout most of the middle of the tank.

Is there a viable plan I can come up with that will allow me to run all the tubing along the perimeter so that I have free reign through the middle of the tank to stack rocks?

I really don't want to scrap the UGJ idea, as it seems so useful and would be so easy to implement right now with the tank empty.

I've brainstormed it a little... all I can figure is that if I do run it along the perimeter, I'll have to partially close off/restrict the jets closer to the powerhead so that the flow doesn't heavily favor those jets. Even then, I'm not entirely sure how I'll do this, and how I'd place the jets...


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## sjnovakovich (Sep 13, 2010)

I would point those two jets in front and angle them back toward the filter intake. The dispersion will push everthing toward the intakes rather than toward the fron corners. I think that the way they are currently arranged could cause some dead spots in the center of each rectangular area. Just my 2 cents.


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## DavidH (Mar 11, 2011)

sjnovakovich said:


> I would point those two jets in front and angle them back toward the filter intake. The dispersion will push everthing toward the intakes rather than toward the fron corners. I think that the way they are currently arranged could cause some dead spots in the center of each rectangular area. Just my 2 cents.


Do you mean the original design (if so, disregard that one... I'd like to delete it but I can't) or the one in the post above yours?


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## sjnovakovich (Sep 13, 2010)

DavidH said:


> sjnovakovich said:
> 
> 
> > I would point those two jets in front and angle them back toward the filter intake. The dispersion will push everthing toward the intakes rather than toward the fron corners. I think that the way they are currently arranged could cause some dead spots in the center of each rectangular area. Just my 2 cents.
> ...


I am referring to the color post, just above my post.


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## skabunga (Apr 17, 2011)

How do you perform maintenance on the powerhead? Do you leave the powerhead in position at the bottom of the tank and just remove the filter on the intake to replace/clean? Or is there some mechanism for easily detaching the powerhead from the PVC structure?


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