Backyard Aquaponics
A place to discuss aquaponics

I just set up two half barrel grow beds and filled them with gravel. Seeing all the loop siphons on here, I thought that would be the easiest way to go. Problem is: I can't get them to work.

First try was using a regular garden hose. The siphon would kick in at the level of the top loop and drain the grow bed. The siphon however doesn't break and once the barrel is almost empty the flow coming out of the hose is the same rate as the stream of water filling the grow bed (which isn't a lot, but it keeps the grow bed empty)

I thought a bigger hose would probably empty the barrel more quickly, breaking the siphon at the end. It does, but now the problem is starting the siphon: when the barrel is full of water, a little stream pours over the top loop of the siphon and it's not enough water to start the siphon. So now the grow bed fills up with water and only the excess water overflows through the loop, keeping the grow bed filled with water.

All information on loop siphons that I have found so far is about how easy they are to set up... What am I missing here

Your intuition is right, but there are ranges of flow-rates that work. Generally speaking, your outflow is going to be about 2x your inflow.

The easiest way to tweak your system is to put a valve on the inflow pipe. You can then increase or decrease the flow to get you into the properly balanced inflow and outflow rates.

I am experiencing the same issue with the half barrels cut the long way. The issue I believe has to do with the varying volume per depth of the barrel. (I didn't have an issue using the half barrels with loop siphons in the barrel ponic system due to the flush tank intermittently filling them. However with a continuous flow into the half barrel I am experiencing trouble.

(Just an FYI, all my loop siphons in my regular straight sided grow beds have been ticking along no problem.)

If I get the flow fast enough to start the siphon when the barrel fills, the flow rate is too fast to let the siphon break if the flow is slow enough to let the siphon break, it won't kick in properly the next time.

Here is where some of the other siphon tricks can come into play.

Perhaps try putting some elbows at the bottom of the siphon tube. For some situations this will cause a lock so that the siphon can't really trickle over until there is enough pressure to push the lock out of the way and fully start the siphon.

Conversely, you could add a breather air tube from part of the loop (usually the top) of the siphon to just above the height of the desired low water mark in the grow bed. (I've never tried this on a loop siphon yet.) This should allow air into the loop, breaking the siphon when the water drops below the breather tube. I have had success with this on small bell siphons.

I've also heard of people using ping pong balls to get the siphons to break but that didn't work for me.

If unable to adjust your inflow try adjusting the, (radi) of the loop. Tighten it up a smiggin and it should help with the break.

pictures would help us diagnose the problem.

I gave up tinkering with my loop siphon on the half barrel bed yesterday and stuck a little pump on a timer on it and restricted the drain enough that the barrel fills up and then slowly drains while the pump is off.

I'm supposing that my drain size on that bed my just have been the perfectly wrong size for a loop siphon in a barrel with the way the volume changes as it gets deeper. I know people have gotten loops to work on half barrels, lots of em. I was trying to do it using 3/4" thin wall pvc connecting to an elbow and then a barb to hook up 3/4" ID vinyl tubing for the loop. I suppose part of my problem with adjusting that grow bed is how it's situated and how I put the drain. Not easy to tinker with.

Good luck!

Thanks for all the suggestions!

I've spend most of today trying to get this to work, but it's still not working. I think I'm going to abandon the loop siphon.

I'll get my barrels hooked up the high-tech way. I'll go digging in my electronics box tomorrow, I'll probably have some sort of micro controller in there doing nothing. I also have a pressure switch that I can use to monitor the level of water in the barrels, these switches are normally used in washing machines to keep an eye on the water level and prevent a flood in your house.

The micro controller will be programmed to run the pump until the barrels are filled to the desired level and the pressure switch kicks in. After the pump shuts off the controller will count down to the next cycle start.

Working with electronics and programming is right up my alley

Don't give up just yet.

no reason you couldn't run a breather tube back into your GB, the same concept has been used with bell syphons. Tee a small tube off the top of the loop, and run it inside the growbed down to just above the base of the syphon. This will suck air into the loop when the water level drops below the opening of the breather tube and break the syphon.

I used a siphon of sorts to speed draining of my fish tank for my CLIF-PIST setup. I placed a air tube in the "loop" to break the siphon where I wanted the level to be.

I've switched pumps, so now I can regulate the flow and the first loop siphon is working
I don't see any problems getting the second one to work now. I just have to tweak it to kick in at just the right level.

Luv it when those suckers do what they're suppose to ..... persevere Nico... it's worth it in the end.....

Hi Nico, what size tubing did you eventually get it to work with? 3/4?

-ellie

I'm using standard garden hose with an inside diameter of 12 mm