Backyard Aquaponics
A place to discuss aquaponics

So after a lot of reading and a lot of watching youtube, and oddly finding out about aquaponics from looking at geodesic domes and stumbling upon Rob's massive project, my wife let me make a test system in our living room. We had a 10 gallon aquarium around the house, so we decided to use that as the starting point.
We walked around the local home depot, and found what looked to be a good grow bed. Lots of back and forth to the store and we finally seemed to have a system in place. We have a small pond pump going through 1/2 inch tubing to flood the bed. The stand pipe is a piece of 3/4 inch PVC. For the bulk head, I used electrical PVC connectors and some "O" rings. I constructed the bell siphon out of 1.5 inch PVC, with some air hose as a break and a small plastic pencil sharpener cover attached with silicon to make sure the air hose had time to break the siphon.
Now though, I have a problem, my stand pipe is about 9 3/4 inches off the bottom. My bell siphon sits at just about 11.5 inches from the bottom at the peak. My water level rises to a bit more than 1.5 inches above that before the siphon kicks in, and I can't seem to think of why. This puts me precariously close to overflow, and makes me want to watch the system 24/7.

I have more pictures to attach.

Hello and welcome.

What size is your bell (diameter) and what size is your standpipe (diameter and height)?

The bell diameter is 1.5 inches, the stand pipe is 3/4 inches. The top of the standpipe is 9 3/4 inches off the bottom. Already the biggest lesson I have learned is make sure the media filter is wide enough to get your hand in wide enough to grasp the bell. Thankfully the wife has smaller hands.

I would think that the difference in diameter between the standpipe and the bell are not large enough to allow enough water in to create a siphon.

I would say the siphon is only starting when there is enough pressure from the volume of water in your growbed to force water through.

Can you try a larger bell?

I will give that a try when I get a chance to go back to home depot. I am probably glad I haven't been keeping a running tab on the cost of this system. So many lessons must be purchased, some must be dug out of your grow bed, but most times you get to do both.

Welcome to the AP life, chanuga.
I don't have lots of experience with siphons, but maybe the piping at the bottom of the siphon drain is the problem. Is it connected solidly from your bulkhead all the way across to where it drains to the tank? An air gap at the bottom of the bulkhead may help start and stop your siphon.

Any of you siphon experts out there agree?

Looks like a nice little system!

I am new as well... But I think I agree that the bell is to small. Is it sch40 (thick) or SDR (thin) pipe?

On my IBC system I have a 3/4" stand pipe and I plan to use a 2" bell. For testing purposes I used a 2L soda bottle (4" bell) and it works like a champ!! If you dont have enough volume between the stand and bell then there is to much friction...If you have more fall in the drain pipe it may counter some of that friction. And you also need to have enough head space (top of stand / roof of bell) to not cause excess friction.

Maybe try a clear bottle (soda, water, ect) so you can see how your system works..

something else I thought of as I was working on my system.. Is your pump to big or drain to small for the pump? Can the drain handle the pump with out the bell?

Try removing the bell and run the system.

I've gotten some time to do some more work on the system, so let me reply to some of the questions. I got a 2 inch diameter bell created, it is about half an inch shorter than my 1.5 inch bell and when I put it in the system the water level still goes up to the level it does with the 1.5 inch bell.
I have created everything using the thick version of PVC or ABS. With the two inch bell, I am unable to get an air trap around the tube (the pencil sharpener plastic), so I also have a problem with the siphon stopping once it begins. This is after I have cut the air tube at a 45 degree angle to create a bit of space. I don't think I have a problem with pump or stand pipe size. The pump feeds into half inch tubing and I have the ball valve turned down a bit to restrict flow. Also, if I remove the bell, the system fills to the top of the stand pipe.
One detail I didn't mention, the drain pipe back to the fish tank runs slightly uphill. Maybe it is needing the extra pressure from the water weight to push through that. Also, due to the noise police (wife) I have the water draining below the water surface. I'm not sure if that has anything to do with it though.

I wish it were easy and I had more space to put more rocks in to give me the depth to keep down algae growth. I guess I have to dig it out and test a lot more.

With that drain pipe running uphill, it will mess with your siphon for sure. Need to correct that somehow. Also check out affnan's silencer setup for draining back into the tank-though I persoanlly enjoy the sounds of siphons regularly flushing and burping. I guess that description explains why a woman would not appreciate it.

I sometimes have problems with my siphons when the water level in my sumps are very high and the pipe is under water. The beds tend to turn into constant flood beds, but I dont notice the water level getting as high as what yours (but my beds are 2sqm in size).

Can you try it with out the drain pipe returning the water to under the water level of your fish tank?

If that works, the look at implementing Jimbo Rollins suggestions (air gap just under the exit from the grow bed or Affnan silencers). The other suggestion from Unclejuju of removing the bell is also very valid.

The return pipe running slightly up hill wont be a problem.

I got it fixed finally. After some measuring, my "slightly uphill" was more like 2 inches uphill over a 12 inch run. I put a couple of pieces of 2 by 4 under the grow bed to raise it 3 inches and the siphon started working at the right level. Now all I need are goldfish!

the Petsmart here has small comet goldfish for 13 cents each and slightly larger ones for 27 each. Tough to beat.