Backyard Aquaponics
A place to discuss aquaponics

Hi HB, I would want more vertical fall between the bottom of the GB and the top of the FT. I don't think it will initiate and keep going if the loop ends so close to the level of the other end of the loop. I.e. it would work more reliably if the end of the loop is a good amount lower than the start of the loop.

I have heard that before too DD, but mine all end right out the bottom of my barrels, and work great...aparently putting an upturn at the end of the siphon can keep it primed enough to start quickly too.

Hmm, well I'll be a monkey's uncle.

Keep your siphon short.
keep it as straight as possible, fewer elbows is better
let it dump freefall into your drain
keep the outflow as vertical as possible, (some ppl like putting two elbows in the bottom, so outflow is now up, and a small reservoir is always present. This decreases the chance of a partial start)
More head (raise the GB) will cause the siphon to perform better.

ummm these are the best I can think of.

I tried the small pump from Harbor Freight today and it fills the empty GB in 18 minutes instead of 6, so it may work better at not being too often. I'm still finding the siphon flow gets much stronger if I submerge the end of the siphon tubing. Left just hanging there the outflow pretty much equals the inflow of the pump and the water level doesn't drop, even with the weaker pump.

I'm thinking if I could find some kind of float to act like a flapper valve to break the suction of the siphon for even a few seconds it would be enough. Has anyone done this? One problem is the inside drain is vertical, which would make it harder to get a flapper to close, I think? Another problem is how to attach the float or assure it's proximity to the drain pipe.

At this point I guess I wish I had put the drain hole in the bottom and used a Bell siphon instead, even though it is inconvenient....

HB

Well, during the time I was writing my post several people posted. I can try the elbow at the end to keep it primed instead of submerging the end in the yogurt cup. I still don't see what will break the siphon. I did have a longer tube extending down into the FT and also I raised the GB so it is just above the FT so if something happens to either bulkhead it will leak into the FT. Tomorrow I'll try some more tweaking of the end of the siphon hose.

Thanks and g'night,

HB

I think i saw a post somewhere else where someone had used a blue rubber ball that would float to help break the siphon.

The use of elbows (yogurt cups or submerging the end of the tube) at the bottom of the outlet of a siphon (either bell or loop) basically traps a bit of air in the tube for a little while which forces the water level in the bed to rise a bit higher above the siphon before it has enough weight to push the air bubble out and start the siphon. The benefit of this is the bed is less likely to get stuck at the flooded type of equilibrium. The other side of this is that when the bed is almost drained, it is more likely that the siphon could get stuck "on" and not be able to get that gasp of air needed to stop the siphon. In order to make this happen easier, the breather tube can help by creating a little air bypass to get some air further into the siphon quicker and allow it to stop. Otherwise the weight of water falling in the downward part of the tube often just keeps pulling more water after it even if some tiny bubbles of air come along too.

Most my loop siphons drain into open drains (no elbows or submerging.) None of my loop siphons require breather tubes.

I do have one bell siphon with elbows on the bottom end and that one does require a breather tube.

It sounds to me like your inflow might be just a little too slow for your loop siphon, hence why you need to submerge the end of the hose to get it to kick in fully. The pump needs to fill the growbed faster than the loop can trickle over in order to fill the loop enough to really start the siphon fully. Or you can go with the elbows and breather tube.

Good luck with it.

Well, I tried 2 elbows, I'm working with vinyl tubing and polyethylene elbows, and that didn't work. Today I tried one elbow and stronger pump, it wasn't doing well, then the small Harbor Freight pump. The loop siphon tube comes down about an inch, 20 mm, below where the siphon exits the GB. With the elbow the loop siphon did manage to kick in, and get strong enough to drain the GB. When I was not observing it also seemed to break the siphon, mysteriously. I also managed to break the siphon, as I tied a badminton birdie in front of the exit pipe so as the water level dropped it sucked the ball of the birdie toward the pipe just for a second and it was enough to break the siphon. I don't suggest this as a permanent solution but it was nice to have it work some today.

I am pressuring myself by having started my seeds already, and the beans are stretching out, so I'm going to put in gravel tomorrow because I think it is tweakable now in the tube I will have to keep gravel out.

TCL, when I tried the stronger pump it was too strong for the siphon. The water level wouldn't drop. Somehow the weaker pump seems to work better. I have a bigger stock tank and bigger growbed to work on after this so I think I'll keep the bigger pump for it.

I'm really encouraged today since it was siphoning for several hours, about 48 minutes to fill and drain, and I think that with the gravel in and less water it will be faster, maybe by 1/2, so may come into the range of acceptable F & D times?

I want to do fishless cycling so I would guess for the sake of the seedlings I need to get started on that. I have some duckweed in my aquarium and put some gravel in the bottom to hopefully get some bacteria from the duckweed, so I will put the gravel in the growbed when I get it set up and hopefully start things going.

I was reading good comments about lava rock. Is this better than pea gravel?

Is there a safe fertilizer I can put on the seedlings at this point, which are in Hydroton and plain water, or should I just get some ammonia into the system and get the bacteria started?

HB
Support bacteria, they're the only culture some people have...

HB my loops were just loops and didn't have breathers or elbows either. If once the gravel is in, that the siphon doesn't stop try bypassing some flow or try a wider hose diameter. If it doesn't start try a narrower hose diameter. Things will definitely change when there is gravel in there, and they can change a bit further between clean gravel and mucky gravel with roots in it.

To fishless cycle get some urea, and some seasol / maxicrop.

Gravel will halve the cycling time.

I got most of my GB filled with gravel yesterday. There was some fine stuff left to cloud the water a little, but it seems a little better today. I also built part of a pvc structure to hold lights over the plants and also provide support on which vines can grow. I'm realizing it will really limit my access to the bed and especially to the siphon/standpipe area, particularly after plants are growing there. I hope I get all the kinks worked out soon. The badminton birdie is helpful sometimes but also once stopped up the loop siphon so the water went up to the SLO overflow. I guess I'll have to dispense with it.

HB
Have you ever imagined a world without hypothetical situations????

I got my plants in little baskets into the gravel last night and hung the 4' fluorescent light, so now I have plants growing, am trying to start cycling ammonia, and can get at least one side of the loop siphon to perform without intervention. I'll have to keep tweaking.



HB
If a parsley farmer is sued, can they garnish his wages?

Well, I just pulled the elbow way back toward the GB and tied it so the free (outlet) side is at about a 45* angle, and now the siphon both starts, gets strong, and shuts off by itself! It took 12 minutes for F & D. That would make 6 x an hour, which seems excessive to me. But, progress!

HB
Love means never having to say, "Put down that meat cleaver."

Oops, 5 x an hour.

HB