# DIY overflow for DIY sump?



## LS70

*DIY overflow help*

Hi 

i am considering building a DIY Sump out of my spare 10g (will be used for a 38g) 

googled a bit but still have a few questions

*1. does an overflow start to syphon automatically after power comes back on? (since pump will increase water level once power is on...)*

I am debating just a normal syphon vs overflow box. 

with normal syphon, if power cuts out, you get an air break, eventually something break of flood once power comes on correct?

here are my considerations


















*will the 2nd image (diy overflow pipe) begin to syphon automatically? this is my main wish*


here is something i started but i cannot get the syphon to start from the overflow side. this is just a test with 1/2 OD barbs, Comments? 

this would be perfect since it is clear and much more discreet then the PVC


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## TheOldSalt

A right & proper overflow does NOT experience a siphon break upon power outage, so it therefore does restart once the power is restored.


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## jones57742

L7 and TOS:

Both you fellers have me completely lost.

IMHO, only two types (and this is like physics in getting back to the basics) of wet/dry overflows exist: drilled tanks and siphon tanks.

L7 I reviewed the photographs and am really lost.

In the siphon tank world we have intake orifices which are near the bottom (and hence have a siphon break hole in the return tube near the surface to prevent sump overflow) or high intake orifices but in either case the siphon is broken when the return pump fails.

Can yall please explain?

TR


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## TheOldSalt

A proper overflow box has a dual-chamber arrangement on each side of the glass in which both ends of the U-tube stay submerged at all times, even when water is not actively flowing. This keeps the siphon from breaking. Water can only drain out of these inner chambers so far, thereby keeping it retained in powerouts, but while the pump is running the excess water flows over the sides of the inner chamber, in to the outer chamber, and down the drain hose.
The overflows in this picture replace the dual-chamber arrangement with a single chamber and a standpipe. The siphon's ends are well below the height of the standpipe, thereby keeping the siphons from breaking. This setup isn't quite as effective and is prone to clogging, but it should work well enough most of the time.


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## jones57742

TheOldSalt said:


> A proper overflow box has a dual-chamber arrangement on each side of the glass in which both ends of the U-tube stay submerged at all times, even when water is not actively flowing.


I understand TOS!

TR


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## k-dawg-

3 basic options:
best:
http://www.lifereef.com/siphon.html

good:
http://www.melevsreef.com/acrylics/overflow.html

decent:
http://www.reefbuilders.com/forums/...etting-up/9757-diy-pvc-overflow-question.html


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## jones57742

kd:

I really appreciate the links.

TR


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## k-dawg-

jones57742 said:


> kd:
> 
> I really appreciate the links.
> 
> TR


No problem


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## LS70

Thanks for the links 

the 3rd one was a new one, i think i will follow that design, 

the only other problem i have is finding the materials! 

i went to Rona and Home Depot; they have the white 1in PVC but all the white PVC fittings are threaded!! (except for the valves) am i suppose to thread the pipe with the fittings? i though i could just use PVC cement.


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## k-dawg-

That's strange I've never been to a HD that didn't sell slip pvc fittings, Do you have a Lowes in your area. I personally wouldn't try to glue threaded fittings together. JMO HTH

EDIT: By the way the overflow you linked in your second picture is the same design


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