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Cheap Overflow


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trmiv - there is no gurgling because i installed a 90 deg elbow to the rear box bulkhead...it stops the air from getting into the water stream.


myfisharemean - That would not work because you would lose your siphon when the intake box empties out, or when air gets in through the sump end. If your sump was about the same waterlevel as your tank, then you might get something working.

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What kind of pump do you have feeding the return? I see SCWD on there, do you get good flow with it? Overflows and sumps scare me though, I don't want it to flood.

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Does that thing self prime at all once it's been going?if it's set up right, the ends of the U-tube should remain under water all the time, even during a power outtage, or am I on crack again?

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If you look at the pictures you will see that the end of the U-tube on the sump side is below the drain, so if the power goes out it will keep the siphon... or at least it looks like it is.

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trmiv - it's got great flow, i'm using a Mag 5, and even have the use of a ball joint before the tank return because flow rate is too high! without the ball joint, i get a sand storm.


Perpetual98 - revance was right on the money. You only need to prime it once and the siphon is set. The flow-rate is soo good, that any air bubbles that get into the U-Tube is shot straight out the back end, so I have very little worries that this thing will flood on me.


quiksilver5768 - you can get it at K-Mart. Krylon Fusion rocks! i use it on a piece of plexi that I cut to the size of the tank's back...I painted the plexi to fade blue to darkblue by masking the layer with black paint. Now I can change the background colors by replacing the piece of plexi.

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The bottoms are gonna be about even, and the fuge is gonna be a 5, and the tank's a 10 hex. I was gonna have a U-tube attched to a aquaclear (or like) surface skimmer, then run it straight to the tank, with the venturi-siphon-starter thing on it. Then I saw your post and thought that would be better than the surface skimmer.

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could you use this krylon fusion paint on pvc fitings? I would like to paint my bright white pvc fittings which act as a part of my return for my sump black...

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quiksilver5768 - I wouldn't try it because the paint could release chemicals in the water...but I'm no expert. Start another thread for PVC paint. I've seen PVC paint available online, but it's pretty pricy.

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melcolm, how much would you say the whole thing cost you? i went lookin for those specimen containers at lfs today and man, what a rip off. the only one i found them at they wanted like 20 bucks for two

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jimbofromfrag - costs (from memory):


- From LFS -

1 Lee's medium specimin container (intake) ~ $8

1 Lee's Large specimin container (rear) ~$5

1 U-Tube (for siphon action) ~$4

- From HomeDepot -

1 acrylic bolt/wingnut (to attach the intake box to the piece of plexi) ~ $2

1 PVC 1" male adapter ~ $0.45

1 PVC 1" female adapter ~ $0.45

1 rubber gasket to fit under the rear box through PVC ~ $0.45

- Other -

1 scrap piece of plexi (to hold the intake box) ~ $free

+a small sheet would cost you about $3 at Home Depot.


TOTAL : about $20 - $25

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If I owned a dremel, I'd do this. But with the cost of the dremel, I might as well just buy one off of ebay. Either way, this is an awesome DIY.

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What size tank is that on in the first set of pics? I was thinking of doing an overflow to a sump to get the unsightly stuff out of my 10 gal, but most overflows I see are way too big. This may just work...

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any way you could do this without a dremel? or do you think the plastic would crack?

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You could probably cut notches with a table saw if you've got one. That's how I got notches in the baffles of my sump.

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cool. i think i'm gonna go ahead with this little project. i've been dyin to add a sump w a dsb and fuge to my 20 long. plus the added water volume might let me add one more fish to the tank (only 3 so far). thanks

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In the first post it says you need a large container and medium one. I can't seem to find the medium one. I can find small and large, but not medium. Is it the small one I need?


Also, where do I get that tubing to go from the overflow to the sump?

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trmiv - it is indeed the small one you speak of. I matched the SKU# in my picture with the one listed here:


Product Link


and I use tubing that is similar to the one listed here:




You should be able to use PVC piping to route the overflow to your sump area with ease.

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ok. one more (stupid) question. how did you get a water tight seal on the outside box? i tried using an o-ring at the bottom of the male adapter (inside the box) but can't screw the female piece on tight enough to get a seal. what kind of gasket did you use and did you put it inside the box or outside? any other ideas you got would be appreciated, too. thanks


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jimbofromfrag -

I had the same problems getting the male-female PVC to fit tightly on the thin plastic walls. The trick is to find a thick rubber gasket at the hardware store. I couldn't find one with the right size inner diameter in stock, so I got an oversized one and cut the center out. I used both teflon paste and teflon tape to use on the PVC threads. The paste is used as a lubricant/sealant, and the teflon tape was just a double safeguard. You'll find tightening the PVC will be much easier using the paste.

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  • 2 months later...
Originally posted by speakeraddict

Should flow between 200 and 300 gph safely.


We used to build these all the time in the 90's.


I ran two on a 74 gallon custom I built and it worked great.  I put a piece of airline attached to a check valve at the peak of the u-tube then attached it to the venturi input of a power head.  That way, if the power went out, the siphon started automatically.




best advice seen in this thread yet


also take note of this design




i will be building 1 like this for myself but will be adding an airline from the overflow tube connected to a power head just in case




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