pvc overflow for others to share

[sjm817]

A poor design example would be a shallow skimmer box, short U Tube, high baffle or overly tall standpipe. This would be a low pressure flow design which would not be good to keep air pushed through. A good design has a deep skimmer box and a long U Tube to maintain strong velocity during start up.

Not set up right is too low a flow through the U Tube to keep sufficient velocity through the U Tube.

I dont like a pump because it is an active part that can fail and the air fitting is an air leak. An air leak is exactly what you do not want in a siphon tube. There are tried and true designs that have been around for 20 years that work reliably without the aid of a vacuum pump. Why go backwards?

 

[Gordonious]

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[impur]

<a href=showthread.php?s=&postid=7844495#post7844495 target=_blank>Originally posted</a> by Gordonious
I do not like that second photo graph you posted though. Looks like your water is rising in the tank a bit to fast for it to keep up with. A little snail popping in the top and slowing it down a little bit could be big trouble. I would slow the pump a little or add a second return. (or build one with larger tubing, but I wouldn't go that far) When myn ran the water level never got more then a mm above my overflow pipes.

I think that was my 2nd attempt on this thing. Next i cut the vent stack down and it sped up nicely. It keeps up with my GenX 1700 easily. Its been running for weeks with no problem.

Its only my quarantine tank, so its rarely running and only for short periods at a time. Works great for this use. I will have an elbow with a piece of eggcrate on the opening while in use.

 

[Cody Ray]

I had something similar to this, it worked but was ugly. For me it is just easier to drill a hole in the side and screw a bulkhead along with a strainger and extrenal durso.