Phillysailor

Easier than a Bell siphon

4 posts in this topic

So I mucked around with s Bell siphon, using a 1” PVC outflow through a bulkhead in the bottom of a 35gal tote, a 1.25” adaptor for wider entry and a 2” and a 3” cap... no luck.

Frustrated, I switched to 1” pipes in an inverted U, but it wouldn’t reliably start. The open end of the tube was just off the bottom of the tote, the height is 6”

Finally, threaded 1/2” tubing through the 1” pipe extending a few inches down the drain. The GB end of the tubing has a fish filter tip.

Perfect. My 290 gpm pump with max lift 5.9 feet is lifting from a sump 3 ft below the grow bed entry bulkhead through 1/2” tubing. A simple valve controls flow, and I’ve been unable to find a setting that doesn’t result in a flooded tank (high flow  3mins, low flow 6 mins) that doesn’t create siphon reliably within a couple minutes of first drain.

I need to restrict the flow of the pump, however, in order to ensure that the siphon doesn’t “reset” endlessly after draining the GB. At the end of a cycle the siphon “breathes” 4-10 Times, and then loses siphon. 

I think the smooth arc of the tubing makes the trapping of air easier to flush, but was pleased it was so easy to construct with slip fitting pvc, no cement. Easy to modify/improve/tinker.

Edited by Phillysailor
Clarity (see edit history)

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Have you considered not using bell syphons at all?  Plants grow just as well without them...as trials have demonstrated...and they are often just an added complication.

bigdaddy likes this

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If you like flood and drain, a timer on the pump, and a double overflow (restricted bottom and unrestricted top overflow) will work more reliable than a bell syphon.

Ravnis likes this

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I've used the U siphon on a smaller basement system I had, and it was flawless. I was actually kind of expecting some tinkering to be needed to get it to engage and break, but, to my surprise, within 3 cycles, I had the perfect flow... The only downside I found, was that it took up more space in the grow bed than a traditional Bell would, but was mucking around with the idea of using an external box for it... 

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