Why an overflow?

[Anonymous]

Why not an underflow?

It seems to me that people are concerned about having enough flow in their tank to keep all deitrus suspended so that it can go down the overflow to the sump to get skimmed. Why not have the slots in the overflow at the bottom of the tank? Then all the stuff that normally collects in the bottom of your tank would be sucked into the "underflow" and go to the sump. Then there would be no need to constantly clean the sediment in the display tank.

Is there a reason I am not thinking of that this would be bad?

Besides the plumbing part about the tank draining all the way to the bottom when the power goes off. I think I have that one solved....

 

[Anonymous]

If you drill the bottom of the tank the drain would allow it completely drain the tank if the pump fails.

 

[Anonymous]

Pulling from the bottom is good but you also need to remove the DOCs that collect and form an oil slick on the water surface.

The AGA tank I have pulls from the bottom (a little) and from the surface (mostly).

I would think that a BB reef tank would want to pull mostly from the bottom.

 

[Anonymous]

If you drill the bottom of the tank the drain would allow it completely drain the tank if the pump fails.

Besides the plumbing part about the tank draining all the way to the bottom when the power goes off. I think I have that one solved....

Hey Guy, what is a DOC? I probably know, but I can't think of what it stands for at the moment.

If I had a bare bottom tank I would set it up like this. All flow to the sump would be drawn from the bottom up into the overflow chamber, and the outside top of the overflow chamber would have notches cut into it even higher so that when my surge device flushed into the tank the "DOC" 's would also get flushed down.

Then a simple vacuuming out the sump would suffice for cleaning as all of the dirt would end up there. As it is now in my system most of the dirt ends up in the bottom of the main tank, and no matter how much flow I have the tank will either have dirt sitting around in the corners, or it will constantly be cloudy because of the deitrus in the water.

I think its time for a plumbing change in the Flanigan household...

 

[Anonymous]

Ok bottom up.. DOC = disolved organic.. compound/component?

You could build an underflow, and I guess if you had that output to a pipe that went UP the back, and loop back around down to the sump, also have a T instead of a 90 that goes higher than the tank with an open top to prevent a siphon then this could work. Also I'm guessing this would become something that could very easily clog up.

*shrug* go ahead and make the prototype knuck!

 

[Anonymous]

How about I make a cad drawing of my idear first?

Then you all can critique it into oblivion....

 

[Anonymous]

You CAD!

That would help me understand what you are getting at.

 

[Anonymous]

Bryan,

Please show us how to do an overflow fromt he bottom without the risk of emptying your entire tank.

If that were possible, I thank someone would have already done it and we'd all be doing it

Louey

 

[Anonymous]

You could still have a standpipe in an underflow, and there are some RR designs that pull water from both the top and the bottom of the chamber.

 

[Anonymous]

AGA overflows have slots in the top and bottom. My 75G is that way. I think most of the water goes through the top.

Louey

 

[Anonymous]

Well I understand a way to do an "underflow" without emptying the tank.. I dont have cad but I'll whip up some MS paint elite skills

I'm unsure how much "suction" will occur at the bottom though, ie how effective this would be to actually remove detritius or whatever, but if this is the only "outflow" you happen to have, and you're pumping in 1000gph, you'll get 1000gph coming out, so should provide some decent movement.

 

[Anonymous]

you have to limit the underflow. Or the overflow won't happen. The water level can settle below the overflow teeth and then only underflow.

The way it's drawn you'll end up with an oilslick on top of your water.

Building an overflow with adjustable teeth at the top would prevent it. Or just use a small hole at the bottom. One that's underated for the return pump.

And the way it's drawn would suck the sand out of my tank, then I'd be pissed my bottom would be bare!

 

[Anonymous]

I don't know, if I draw this all out an one of you gets rich off of it I will be sore at ya!


Hold on, let me put all this guitar stuff away...

 

[Anonymous]

Okay, here is a quick sketch to get you all started thinking.....

 

[Anonymous]

Ahhhh

I crack myself up sometimes.....


the real drawing will have to wait till tomorrow. I just realized its 11 pm and the kids are not here tonight. Just me and the wife.

You do realize that takes precedence over drawing imaginary underflows right????

 

[Anonymous]

You want surface skimming also. All of that dust that settles on the top is sent right to the sump(skimmer).

 

[Anonymous]

Here is an actual drawing

I too used Paint, my free cad program requires me to print my drawings and then scan them to get them into JPG format....


My thoughts should be pretty clear from the drawing.

 

[Anonymous]

I don't think that is really any different from AGA uses in their tanks.

What makes the water flow through the bottom slots?

Just like the AGA overflows, most water goes over the top IMHO.

Louey

 

[Anonymous]

The lower the inside partition is the more water will be taken from the bottom.

You could have a small cutout on the outside partition that will let in 20 - 30 gph. That's enough to keep the surface clean and then the rest of the water will come from the bottom.

I think this is an excellent idea for BB tanks.

 

[Anonymous]

Build one Knucklehead! I don't think there will be enough flow to actually suck up any detritus. At least not anymore than with a regular overflow. You are still dependent on keeping the stuff in suspension long enough that it can get near the overflow to be whisked off to the sump. I also think you will end up with a pile of detritus at the bottom of the overflow.

But make one!