Po mans overflow

[I3u11he4d]

I was wondering if it would be possible to make an overflow out of pvc.Using 1 1/2 or 2 inch pvc for the mouth of the overflow and tapering that down to about a 1" or 3/4" to the sump.I would cut grooves in the larger pvc for guard teeth.It wotld run of suction just like the store bought ones.The one thing im not sure of is how to figure out the gph.The only thing I can come up with so far is to use a ball valve to control the flow into the sump to stay in pace with the pump flowing back into the main tank.Just something I was thinking about and I think I have all the parts I need laying in the garage.Let me know what ya think.Will it or will it not work and why....

 

[hardb0iled]

So do you mean to drill a hole in the bottom of the tank for the overflow (ie. standpipe) or do you mean like the hang on overflows that go over the edge to the outside of the tank?

I'm not sure with the hang on overflows, but with the standpipe, restricting the overflow with a valve or similar is not a good idea. If the return pump gets slightly out of whack with the overflow rate you can end up overflowing your whole tank. You are better off letting the overflow flow its natural amount and restrict the return pump output to match. This way the flow through the standpipe is regulated by the head pressure on it. If the head pressure increases (ie tank water level raises) the flow rate of the standpipe will increase to match(within a range of course). With a valve restricting the overflow rate, if the tank water level increases the standpipe cannot flow more to keep up and the tank will eventually overflow or at the very least pump your sump dry

I have internal corner overflow and use a modified 'dorso' standpipe. This has an air valve that allows you to slightly fine tune the flow of the standpipe but its mostly to prevent a syphon effect with my design. I combine this with a ball valve on the return pump line to restrict the return flow. It works quite well but I still am getting a lot of noise from the trapped air in the drain pipe from the overflow.

 

[I3u11he4d]

Sorry I didnt clarify.An hang-on overflow is wHat I was going for.I cant drill the glass is tempered .The valve on the return makes much more sense.Thanks ,I always like someone else to look over my thoughts to point out the things I may overlook.Anything else look like it may not work well,let me know.

 

[Ornatapinnis]

Are you asking if you can glue together a "U" shaped tube out of pvc and run it to your sump? If that it the question, then the answer is no, you must have a box inside and out side the aquarium to keep the "u" tube primed and to controll how much water is removed from the aquarium. That would be like putting a drain hose in the aquarium.

Was that the question or did I not understand it correctly?

 

[gomezladdams]

I was curious about doing something like this too.As my hob aquamaster needs 4 x1/2"siphon tubes to keep up with its pump output, I dont understand what would be th difference if I plumbed those same tubes to a sump instead.I dont understand how a hob overflow would improve this particular application.Can anyone throw some science at us here?

 

[I3u11he4d]

Are you asking if you can glue together a "U" shaped tube out of pvc and run it to your sump? If that it the question, then the answer is no, you must have a box inside and out side the aquarium to keep the "u" tube primed and to controll how much water is removed from the aquarium. That would be like putting a drain hose in the aquarium.

Was that the question or did I not understand it correctly?

In essence isnt that what an overflow is,just a drain hose?I thought with the up-turned piece w/the teeth cut-outs would control the quanity that was removed.Does the uotside box really serve anyother purpose other than a prefilter?I did a quick sketch of wat I was thinking,hopefully this will help.

 

[Ornatapinnis]

THis would not work very well if at all. THe problem is that there is nothing keeping the "U" tube primed. In fact you would have a very time getting it primed in the first place. (primed means the "u" tube is full of water.) THe "U" tube must have both ends submerced under water at all times to keep it self primed. What would happen in the case of your drawing, assuming that you could get it to flow water (wich you probably could) the down tube going to your filter would gravity drain water out of the tube very quickly so eventually there would be an air pocket at the top of the "u" tube. Your drain will remove water faster than your pump will add water to the tank (in properly designed systems it will). THis is hard to explain properly but I am right on this. (i spent many years trying not to pay money for an overflow box) THis is not an area to skimp on, you will have a flood if you don't get a good design.

What size tank you have? I may have a few spare boxes I could part with pretty cheap.

 

[Clay]

I agree with ornatapinnis.

You can however drill a hole in the pvc (inside the tank) below the water line. That will keep the tank from siphoning too much water out of the tank.

 

[reefman]

you could use that idea only if you had a hole drilled thew the back of your tank below the water line then you don't have to worry about priming you can drill thew the back the only piece that is tempered on your tank is the bottom i did my tank like this and there are no probs been running almost 2 years

 

[Ornatapinnis]

I agree with ornatapinnis.

You can however drill a hole in the pvc (inside the tank) below the water line. That will keep the tank from siphoning too much water out of the tank.

Your Idea is correct for a return line to prevent back siphoning. THis guy is wanting to use this as a drain to a sump.

Good point though, it's important to have a siphon brake on your return line.