Problems with loop siphon

[Mitch Rogers]

Ok let me describe my setup, Its CHOP with a large fishtank 275 gallons draining into 4 growbeds filled with peagravel. The four growbeds are two 55 gallon plastic drums cut in half horizontally (per TCLynx suggestion) to help with using loop siphon. I have them arranged on a small reinforced table with the sump tank sitting between the fishtank and the growbeds. the 2 growbeds nearest the sumptank dump directly downward into the tank and they seem to be working fine but the 2 growbeds on the backside, or furthest away from the sumptank will kick in but they will only drain about 1/2 way down then stop.

Now important here I think may be how I have my tubing, it doesnt actually "loop" but I have it raised so that air should get in at the right time, and that seems to work to start the siphon, then I make sure the rest of the tube goes in an incline to the sump tank. Any ideas what I am doing wrong? would it be helpful If I went and took a few pictures to show what I am talking about? 

 

thanks in advance

 

Mitch

[TCLynx]

The long run down to the sump may be sucking the water fast out of the bed and there fore the water isn't flowing through the gravel or gravel guard fast enough to keep up so the siphon manages to suck in enough air to stop it and there is actually a fair bit of water still in the bed.

 

Perhaps if you can arrange for the loop siphon to drain into a combined drain line near the beds, you might get things balanced easier.

[Mitch Rogers]

THAT sounds possible and I'll tell you why, the peagravel I bought had an abundance of small small rocks, which would prevent quick drainage. good call TC . I need to check that out

thanks

[Mitch Rogers]

TC quick question, if I took one of the  growbeds that wasn''t draining well and put a T joint in to join it via flexible tubing with one of the ones that was draining properly them both into one line, would that help do you think?

 

thanks

[TCLynx]

Hum, perhaps but it is probably more to do with how far away from the bed is the air gap.  By linking them together you may also cause the bed that is currently draining right to have problems.

Mitch Rogers said:

TC quick question, if I took one of the  growbeds that wasn''t draining well and put a T joint in to join it via flexible tubing with one of the ones that was draining properly them both into one line, would that help do you think?

 

thanks

[Mitch Rogers]

OK update on this, I am about to dump the whole concept of loop siphons and go with a timer. I am very perplexed about this issue and I hate not knowing what is wrong but I need to get some sort of resolution so I may just use a timer. Let me update on what I have observed. I revamped my loops and built them out of PVC as I theorized that the soft pipe may have been distorting after being bent and was causing liitle pockets of air that were hard to push out. After building a rigid PVC loop it seemed to work, but during testing I had most of the water flowing into the test growbed I was working on, I had capped the other three off. When removed the caps and let the water flow to all 4 beds, no dice. The water would rise to the level of the loop, then start draining out at the rate it was coming in but the siphon would not kickin, unless I smacked it a couple of times. This seems to me to indicate I need to greatly increase my water flow. My theory is here that there simply isnt enough water in a small growbed to force the siphon to kick on, is that a viable theory? In any event, I even tried hooking two of the beds together and placing a loop siphon between them so they shared that one siphon, couldnt get that to work either. Vastly increasing my water flow is not really an option and even if it was, I am dubious about the siphons working reliably in MY setup, I like to think there is some reason for this issue and I would LOVE to understand what it is, or if my theory makes sense, even if I have to go to a timed pump solution, I just want to know what's wrong, it bugs me that I don't understand the issue.....HELP!

[David Waite]

Mitch definitely need pics. I think your downward leg on your loop is too short.

[Mitch Rogers]

ok thats the best shot I had, I have since implemented a timer but I would LOVE to know what I was doing wrong. I actually cut off the end of the black tubing below so there was only about 4 inches below the drained water line. In other words, there was almost no tail on it after it looped back down and passed the growbed bottom, does that make sense?

I put the growbed on a table and the sump tank directly below it.

and you are correct there was very very little line left after I cut it. it just went a few inches past the bulk head on its way back down to the sump tank.

thanks in advance for any understanding you can add to this

 

[Derek D]

I would make sure the end of the pipe is longer and farther below the top of the loop.  You might also want to add a restrict or/nozzle to the end of the draining pipe so it will create a nice acceleration of the water as it exits.  Also, the drain pipe needs to be larger than the input pipe (grow bed needs to drain faster than it can fill).  

 

You might also want to play with the shape of your loop.  Give it a tighter radius.  

 

Also make sure the end of the drain pipe is not submerged in water.  You really want that water to be flowing freely and quickly so it creates a nice vacuum. 

Mitch Rogers said:

ok thats the best shot I had, I have since implemented a timer but I would LOVE to know what I was doing wrong. I actually cut off the end of the black tubing below so there was only about 4 inches below the drained water line. In other words, there was almost no tail on it after it looped back down and passed the growbed bottom, does that make sense?

I put the growbed on a table and the sump tank directly below it.

and you are correct there was very very little line left after I cut it. it just went a few inches past the bulk head on its way back down to the sump tank.

thanks in advance for any understanding you can add to this

 

[David Waite]

What I am seeing if this is right is you have a kink about 12 inches up. Try to shape that out it is causing some restriction. 2nd is your tail is going down into the bucket. Pull the bucket a little closer and cut the tail off just as it crosses the lip of the tank. Try to make your loop much smaller as above mentioned. Try those and see.