Backyard Aquaponics
A place to discuss aquaponics

I am almost ready to build my system and after much research on the bell siphon have decided to look at the loop siphons also. I will have at least 20 half blue barrel grow beds with a common drain pipe joining them.

I think I understand the principles that make the loop siphons work but want to be sure. I have searched but cannot find a previous thread with a good explanation of how the loop siphon works and perhaps, more importantly, how to incorporate them in the half blue barrels (with good pictures!) . Could someone point out an appropriate thread.

Thanks to all,

TXPower

simmos system has good pics as does my original Tragic Hobby I think it was called. Dunno how to set a link here, just have a quick scan thru the thread topic authors.
Loop siphons are good. Effectively the top of the loop is the max flood height in ur gbs. Make sure you don't scrimp on ur pump. Buy a bigger one than u think u need and if necessary put a return valve back to ur ft to wind back the flow to ur beds. Important ur pump handles small solids otherwise u will forever be unclogging it.
Good luck and we love pics.

tt, thanks, I'll look at your and simmos examples. U bring up another point I was gonna ask about too, pump size.........I intend to have (3 possibly 4) 250 Gallon IBC's in my system with as many half barrels as I can safely accomodate based on my fish load at any given time. Having said that, at full tilt, what size pump in terms of gph would ya'll recommend?

Thanks,

TXPower

A little blurb I wrote up some time ago....

Looped Autosiphon (also U-Bend or Gooseneck)
This is the easiest autosiphon to construct and is easily conceived from a basic siphon. It is constructed as a loop of flexible tubing, with the crest of the loop below the surface of the growing media. A Looped Autosiphon can be mounted internally or externally to the growbed, with the outlet below, directly through the base of the growbed or out the side.

The water begins draining out of a Looped Autosiphon once the water level in the growbed is above the lower level of the horizontal part of the loop of hose. To remove all air from the Looped Autosiphon and start it working effectively, the water level needs to rise to the top of the hose. So if the hose is 40mm diameter, then water level needs to increase by 40mm. Once the looped autosiphon is fully engaged, all air will be expelled from the hose, and water drains from the growbed. When the water level has dropped to the level of the intake of the looped autosiphon, air is again introduced to the hose. This may cause a slurping sound as the siphon breaks. By adjusting the rate that the pump fills the bed, the amount of time spent slurping can be greatly reduced.

Looped Autosiphons work best when the intake of the hose is horizontal, the loop is smooth and round, and the outlet ends in a vertical drop. Care should be taken in choosing the flexible hose. Hose with thin walls will collapse over time, decreasing the flow of water.

...I'll post a link to a pic of my looped autosiphons in a sec...

I'm not really up on pump specs as they relate to electricity used etc per amount of water pushed around a system. You have approx 1000 gallons of gbs and 750 gallons of ft. Your gbs will take about 400 gallons out of ur ft at max pump cycle (i.e. about 40% of ur gb volume, it's a rough guide.) That means ur ft will be slightly less than half full at max water in gbs.

You may consider one or two more IBCs just so they don't drop below say half full when ur pumping. One more would mean u would still have about 150 gallons in each ft at worst, a reasonable volume.

I have a 1500 approx gallon ft system, the water is turned over 50% every 90 minutes on a 30 on 60 off cycle, (airstones 24/7) My pump is 2000 gallons per hour. At the moment I have 500 gallons of gb approx. I would prefer if my pump had 3-4 times the capacity so I could add a lot more beds and keep the same pump.

Do u have a thread running with some pics or proposed sketchups?

I have to say that loop siphons (of the flexible hose or tubing type) are pretty easy to adjust. I have two on my barrel system and am planning to use loop siphons on my big system There are a couple quick photos near the end of my system thread.

My thread

Let me see if I can find some quick photos of the loops on my barrels.

Here is another pic showing the loops as they are running now.

Thanks Janet, tt, and tclynx. I have a better understanding now.

tt, I dont have any pics because I am pretty computer simple and don't know what program to use to sketch and how to add it to a post (maybe you could provide some advice, my computer has the latest and greatest stuff on it). Yes, I can add another IBC or two to address the effects of max flood on the fish tanks, or throttle back on the number of blue half barrel grow beds.

Janet, your explanation is very informative.

TClynx, your pics appear to bare evidence that an actual or complete "loop" in the drain system is not an absolute? Also, what sort of fittings did use use to plumb those loops thru the barrel bung holes?

I am so ready to get to building. In a few weeks I will put my 15 x 30 greenhouse up. I already have most of the materials for my system, so once the gh is up its party time.

Thanks,

TXPower

TXPower,
A loop siphon does not need to be a complete loop. You can make a "loop" siphon with rigid PVC even using elbows and such but most people probably would call that a "auto" or "goose neck" siphon. All really the same concept. The max water level will be somewhere slightly above the top point of the siphon "loop" or whatever.

Some slight flattening of the top of the "loop" can sometimes help the siphon kick in when lower flow rates are involved on the input side.

Also, siphons can be internal in the bed or external. They could even be a combination of both.

I simply used the threads in the one bung cap and drilled out the block and threaded in a 3/4" nipple. On the outside I used a 3/4" FNPT to barb that I connected to that black vinyl tubing. On the inside of the barrel (because the bung holes are a little high up) I attached another fitting 3/4" FNPT (this time straight barb) and added another little bit of tubing to get the siphon to suck from closer to the bottom of the barrel. I covered where the intake is with perferated drainage pipe to reduce clogging. Really just a slight adaptation on the barrel ponics manual method.

The other bung cap without the 3/4" threads, I just drilled a 1" hole and threaded the 3/4" nipple through that and it seems to do well too.

Truth though, it would be cheaper to just cut holes in the bottom of the barrel for your fittings as done in the barrel ponics manual. Fewer fittings involved.

Most people seem to find that a rt angle barb starting the loop somewhere near horizontal seems to work. Then adjust the top height of the loop to the desired fill height of the Grow bed.

The biggest problem with auto siphons seems to be balancing the inflow rate and outflow rate. If the inflow is too slow, the siphon may never fully kick in and the bed stays flooded to the max fill and trickles down just fast enough that the bed stays flooded but doesn't start the siphon. If the inflow is a little too fast, the siphon will kick in but when it is about to suck air and shut off, the inflow is feeding just enough that it never happens and then the bed remains with only a shallow flow constantly in the bottom of the bed and doesn't flood again without tinkering.

If your inflow is way too fast, then the siphon won't be fast enough to drain the bed before overflow conditions happen.



Good luck.

Yep TC, that's why it makes sense to have a ball tap at ur gb. Each bed can individually be adjusted to make sure the flow rate is adapted to get the siphon kicking properly and draining quicker than it fills. It adds a few bucks to plumbing for each gb but gives you a lot more control. Also means if you wish to do some maintenance on a particular bed post harvest, you can just turn the tap off completely and by pass that bed.
TX, my sketchup skills are below pre school standard.
Adding photos is pretty simple, just need a connecting cable between ur camera and usb connection on ur computer. SSave ur pics to a folder then open that folder and click on the ones u want to uplaod. There is a step by step on the forum here somewhere, once u geddit, it's easy.