Bell Siphon

[Christopher Brickey]

 I have been trying to get this bell siphon to work for a week now. i have 2 2'x3'x9" drain tables and according to this pdf doc.: http://www.ctahr.hawaii.edu/oc/freepubs/pdf/BIO-10.pdf I have the measurements right. It works fine without the media in it, but when I add the gravel the siphon will not break. Any ideas? I am at the end of my rope and have seriously considered taking the saws-all to the entire system.

[Christopher Brickey]

 So the bulkhead is 3/4" reduced to 1/2", right? does that mean that the drainpipe is 1/2"? and does the length of the drainpipe matter?

Rob Nash said:

here is a bell siphon how-to by Rob Nash, these cost about $10 to  build. 

i have one that has worked without fail for 2 years now.

http://aquaponicscommunity.com/forum/topics/how-to-build-a-bell-siphon

[Christopher Brickey]

 Can the problem with my siphon have something to do with the height? my gb is only 8in.

[Tom OBrien]

My grow beds are about the same. I'm using 2' x 3' x 8" cement mixing trays from Menards. I did some playing around with the drain tube height to get the fill level where I wanted it, but I'm sure that also affected the siphon cycling.

[Christopher Brickey]

Thomas,

 How is ur siphon working? i suppose i can see about getting a valve to control the flow rate better than the T, it is only a couple bucks. but i do not want to throw more money out the window.

Thomas K OBrien said:

My grow beds are about the same. I'm using 2' x 3' x 8" cement mixing trays from Menards. I did some playing around with the drain tube height to get the fill level where I wanted it, but I'm sure that also affected the siphon cycling.

[Tom OBrien]

Christopher,

They are working pretty well so far. My plumbing and pump arrangement is a bit different than most here, because I'm using the stuff we had in our backyard pond. The pump is on a timer and pumps water up to an elevated rain barrel sump because I didn't want to run the 900 gph pump all the time from a 150 gallon fish tank. I pump for 8-10 minutes and then use the rain barrel valve to control the flow rate into the bed. The setup works, but I'll probably try to make it a CHIFT once the goldfish move back out to the pond.

Did you try playing with the height of the drain tube at all? I had some of the hydroton media get under the gravel guard when I initially filled the bed, so I pulled the tube down to flush it out and I did play with the height of both the drain tube and the siphon. I ended up cutting about 1/2 inch off the bottom of the siphon to get the height to what I thought was right. I also fiddled with the PVC drain tube height some by adjusting it up and down. I ended up cutting the small plastic air tube a little shorter as well.

I'd suggest you try adjusting the drain tube up or down a little first. That is a no-cost change and it might help. It can't hurt much if your siphon isn't working now. Experiment with it a little and see if that helps. If your siphon starts but doesn't stop, I think cutting a little off the plastic snorkel tube may help as well.

TKO

[Christopher Brickey]

 yea it starts and does not stop. until recently when i cut the tabs on the bottom of the siphon to 2in and it does not start, it just kind of trickles out. but when the tabs were 1/2in the siphon would not break. as far as adjusting the height can i just unscrew the overflow tube a bit? i loosened it before i drilled holes in it because i figure that that way i would not have to drill the holes, but it did not leak, lol. which would have been good in other circumstances, but bad in that one, lol. anyway the real question is, is it going to affect the siphon negatively if there is a bit of an air leak on the bottom of the overflow tube?

Thomas K OBrien said:

Christopher,

They are working pretty well so far. My plumbing and pump arrangement is a bit different than most here, because I'm using the stuff we had in our backyard pond. The pump is on a timer and pumps water up to an elevated rain barrel sump because I didn't want to run the 900 gph pump all the time from a 150 gallon fish tank. I pump for 8-10 minutes and then use the rain barrel valve to control the flow rate into the bed. The setup works, but I'll probably try to make it a CHIFT once the goldfish move back out to the pond.

Did you try playing with the height of the drain tube at all? I had some of the hydroton media get under the gravel guard when I initially filled the bed, so I pulled the tube down to flush it out and I did play with the height of both the drain tube and the siphon. I ended up cutting about 1/2 inch off the bottom of the siphon to get the height to what I thought was right. I also fiddled with the PVC drain tube height some by adjusting it up and down. I ended up cutting the small plastic air tube a little shorter as well.

I'd suggest you try adjusting the drain tube up or down a little first. That is a no-cost change and it might help. It can't hurt much if your siphon isn't working now. Experiment with it a little and see if that helps. If your siphon starts but doesn't stop, I think cutting a little off the plastic snorkel tube may help as well.

TKO

[Tom OBrien]

By overflow tube, you mean the center (drain) pipe in the siphon, right? I haven't tried drilling holes in it yet, but I saw that suggested as a way to avoid water staying high in the bed if the input stops and it sounded like a good idea. I don't know if that would hurt the siphon performance though.

I understand by what you said about unscrewing the tube that you have a bulkhead connector through the bottom of the bed instead of the rubber uni-seal. Is that right? If so, you should be able to adjust the height some by unscrewing it. I used the uni-seal rubber fitting, which makes height adjustments on the center PVC pipe easier to do.  

[Christopher Brickey]

 yea we r talking about the same tube/pipe. what is the technical term? i forgot. i am glad we r talking about the same pipe because i had confusion on that also. how do u like the uni-seal? i tried like hell to find one but unfortunately couldn't (except on the web where shipping made it unfeasible) so i was forced to get a bulkhead. so yea that was what i was wondering if i unscrewed it to lengthen the height if that would mess up the siphon by allowing to much air in at the bottom, but it doesn't seem to leak when i unscrew it though. i also heard of people drilling a hole in the bottom of it, but since the siphon works on air i am wondering how concerned should we be about air leaks and where? i still have not been able to get the valve for the pump tube, but i will try that and let u know if it works soon.

[Christopher Brickey]

 btw sry if i asked before but... what is the length of ur tabs at the bottom of the siphon? i am pretty sure that mine r to long now.

Thomas K OBrien said:

By overflow tube, you mean the center (drain) pipe in the siphon, right? I haven't tried drilling holes in it yet, but I saw that suggested as a way to avoid water staying high in the bed if the input stops and it sounded like a good idea. I don't know if that would hurt the siphon performance though.

I understand by what you said about unscrewing the tube that you have a bulkhead connector through the bottom of the bed instead of the rubber uni-seal. Is that right? If so, you should be able to adjust the height some by unscrewing it. I used the uni-seal rubber fitting, which makes height adjustments on the center PVC pipe easier to do.  

[Tom OBrien]

Christopher, The uniseals work great. I bought 6 and will use up the last one on my trout project. I got the uniseals through a search on Amazon.com (for "uniseal" or "pipeconex" or something like that) and I don't remember the shipping being that bad. The actual retailer was an Ace hardware store, but don't waste your time on the Ace website because they don't show it. They also sell them on this aquaponics website under the shop tab above. I used a bulkhead connector in my first grow bed, but that was more than twice the price of the uniseals.

I think the tabs on the bottom of my Bell pipe are about 3/4" high. I didn't really measure. I just made a guess, but they are probably 1-1/2 times the width of the hacksaw blade if that helps. I'm not sure that long tabs will do anything bad though. Worst case the siphon stops early and you have a little more water left in the bed than you would like.

[Christopher Brickey]

 well when i increased the height on the tabs to 2 in it stopped siphoning. that was the only thing i changed so it had to be related. i know 2 in is ridiculous for a siphon that is only 6 in. but when i increased them the first time it worked for a longer period of time so, of course i assumed i should increase the length even more, lol. 

 yea i kinda wished i could have got ahold of the uni-seals before i got the bulkheads. i just looked it up on amazon and shipping (3$) is not as bad as wat was on the site that i looked at. they (i forget who "they" were) were trying to charge 20$ total for shipping and processing for 2 of them, lmfao! still i only paid 2.30 ea for my bulkheads a mile down the road. i will look into it next time i need some. maybe the store will order them for me if they r not in stock? so good heads up on the ace thing.

[Christopher Brickey]

 OK i think that the siphon is now working. i know that i have said that before, but now it has been running fine for 17hrs. because of my earlier experience i am waiting nervously to see if it will continue to work. so anyway the things i cahnged was that i put a 1/2in T on the hose running from the pump (to slow down fill rate) and i raised the height of the overflow tube (TYVM Thomas for that one!). seems fine now, but i will update if anything changes.