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Starting the siphon to an overflow


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My friend gave me a complete wet/dry setup. Includes the wet/dry (possible fuge plans coming up! hehe), a skimmer, pumps for the in the sump skimmer, return pumps, hoses, and a overflow. The overflow is the kind that overflows into the first chamber and then the U tube sucks the water from that chamber into the next chamber where it is brought down the hose.


I want to set this up ASAP- but I am curious as to how I am going to get the siphon started after loosing electricty. Theres no nipples to plug a PH into, so what should I do?



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To get it started the first time insert an airline tube up one end of the u-tube, put the u-tube in place, fill each side of overflow with water, then just suck the air out of the u-tube using the airline tubing. Then just carefully remove your airline tubing.


If your overflow box is any good it won't lose siphon during a power outage. In order for this to work there needs to be water in both boxes after the power goes out. Here is a sketch of how it SHOULD work.

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lol I get what your saying.


My overflow does have a baffel so this will work. I appreciate the help.

I was thinking I had to get a venturi driven powerhead or something, u know?

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I have one and love it! I've "simulated" power outages several times for various times.....always restarts!


The PH is only if the overflow (like the CPR) has the bleed valve on top.

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Are the overflows with u tubes just as good as the cpr overflow with the big "channel" inside it? Ive heard of some people complaining of U tube overflows, losing siphon etc. I'm in the market to buy an overflow right now but I dont think I wanna shell out the extra cash for a cpr.

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The reqular U- Tubes works fine, is you need more flow, just add additional U-tubes. the real trick to keep micro bubbles from collecting at the top is to have enough flow. (if too many builds up it will break the Siphon and overflow the top tank) In my experience a 1 inch ID U-tube overflow should have at least 300 (actual) gph pump (like a Mag5 pumping up 4feet from the sump)


You sould always have some measures of turning off the pump if the water gets too high in the top tank. your siphon might break or blocked. (you never know)

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Hey Ag,


I always heard the opposite.....The CPR-type catch air and lose siphon easier. Like insider said, bubbles actially flow through my U-tube.


I got mine from a guy I ebay for $45. It's rated at 750gph. All I did was build a stockmen standpipe and it is super quiet.

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do you have a picture of the standpipe? I have no idea what that is. I did some calculating tonight, looking at the headloss of the pump(mag 9.5) and scwd, Im probably running somewhere between 720-765 gph, it may be less than that since i wasnt able to calculate the additional loss for when each return line has 4 90's in it. I do have a ball valve at the output of the pump so i can tinker around with the flow to make sure everything can keep up.


overall the pump is pumping 4 feet 4 inches straight up.

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Thats a pretty good link on how to build one. I didn't use the coupling (piece #4), as the reducer was big enough. Also, rather than using holes, I used a dremel to cut 2 5/8" slot on opposite sides of the tube. Basically, you want the "overhanging" piece (whether it is the reducer or coupling) to penetrate the water deeper than the slots or holes. That way, the only air going in is from the holes drilled in the top....no slurping!


Just insert it into the outflo of the overflow and "Bingo". If I remove it it sounds like a typhoon. With it it is virtually silent.

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