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Which prefered siphon drain growbeds??

Is there a siphon that is fairly simple and works consistently? Like the idea of a loop. Understand it has problems also. Wonder which size pipe to use for a 4 by 6 by 1ft. growbed.

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Permalink Reply by Lonny Harper on May 13, 2011 at 4:57pm

I think the siphon drain will be approximately 3 inches above the sump water level when sump tank is full. Will this work? If the siphon drains straight out, will there be any problem maintaining a siphon to drain the bed?

Permalink Reply by TCLynx on May 13, 2011 at 6:13pm

It is hard to know, some siphons have no problem having their drain ends in the water and others will have trouble cutting out and getting a gulp of air (this is where the breather tube comes in.)

Permalink Reply by David Waite on May 13, 2011 at 8:34pm

Lonnie you dont need 8 inches if you are going straight down. I helped my friend build a bathtub system and we went straight down into a 3 in drain pipe. So straight out of the bottom of the tub was 2 (90 ) degree elbow into the drain. My system has only 4 inches from gravel bed to raft.

Lonny Harper said:

Another 8 inches question: I'm building my tanks right now...Do I need eight inches if the bell drains straight down into sump tank? Is the 8 inches of vertical pipe needed to create the venturi affect? I might have to re-design my system. Right not, I Plan on having the grow bed just a few inches above the sump. I thought if it drained straight out, that it would be okay. Am I wrong?

Permalink Reply by Chris Leon on May 14, 2011 at 11:12am

I usually get myself into terrible trouble when people bring up the subject of Bell Syphons… I hate the things!!!

They’re much too simple a device to work reliably through the range of input/output flow rates, hampered by restrictions in the grow bed media, temperatures, pH, etc… But people insist that they work reliably day in, day out, month after month and year after year without missing a single beat.

Who here would go away and leave their precious, lovingly cared for crops, for a couple of weeks holiday, to an irrigation system that would be diagnosed with ADHD if it were a child..?

The god of all wisdom on the subject of Bell Syphons seems to be some guy called, Affnan (or should that be Naffman..?). Far too much adulation is heaped upon this man because, at the end of the day, almost any shape and size Bell Syphon will work once the input and output flows have been adjusted correctly. We’ve all had one working for a few minutes, hours, days, even weeks, but, we all know it won’t last and that the next cycle, could be it’s last.

The trick is to keep the input flow constant, the path of the water through the media bed constant, the output flow constant, the temperature stable and the chemical composition of the water within a few PPM. Easy? NOT!!! They’re just too simple to work through the range of variables that they encounter (a bit like our last Prime Minister, Gordon Brown).

If they worked reliably, you’d be able to buy one commercially!!! Wouldn’t you..?

Truth is, if you bought one of these from a retail outlet with your hard earned money, you’d be demanding your money back after a week of pissing about trying to stabilise the bloody thing! In fact, you’d probably drag the shop assistant across the counter and beat him to death the aforementioned device through sheer frustration.

For those of you waiting for me to offer a more reliable solution, I’m sorry, I don’t have one.

I hear tales of how wonderfully simple the ‘loop syphon’ is but, same story… The only thing simple about them, is the person who is prepared to spend the rest of his life ‘babysitting’ it and resetting it on an indeterminate amount of occasions…

Sorry to be so negative on my first post :-(

Chris

Permalink Reply by TCLynx on May 14, 2011 at 7:54pm

I do leave my system regularly. I've got one bed been running with a loop siphon for over the past two years. Another bed has been running with a goosneck siphon for the last 10 months. Now I've got a FLOUT feeding several beds.

A FLOUT is a far more reliable device but it takes up more space than a siphon.

Ya know, a timer or a pump can malfunction too.

Permalink Reply by Lonny Harper on May 14, 2011 at 8:52pm

Well, TC, you've mentioned FLOUT two times now...I guess I'll look it up.

Chris, a perforated stand pipe sounds pretty fool proof.

Permalink Reply by steve on May 14, 2011 at 9:47pm

Thanks for your brutal honesty Chris. I do appreciate that. How about a flap like is in the toilet tank with a float attached. Water rises float lifts flap and flush away?? Anyone tried this?

Permalink Reply by Chris Leon on May 15, 2011 at 1:58am

Aww, bless… There’s always a few delusional people that insist they have the only reliable Bell Syphon in the world. They set it up and it never falters in it’s years of relentless service.

I thought I’d explained in simple enough English why these devices are not reliable. I obviously overlooked the fact that some people have a ‘Syphone Fairy’ that visits in the dead of night and cleans, adjusts, and resets their apparently unfailing contraptions!

TCLynx said:

I do leave my system regularly. I've got one bed been running with a loop siphon for over the past two years. Another bed has been running with a goosneck siphon for the last 10 months. Now I've got a FLOUT feeding several beds.

A FLOUT is a far more reliable device but it takes up more space than a siphon.

Ya know, a timer or a pump can malfunction too.

Permalink Reply by Mike Konshak on May 17, 2011 at 7:31pm

Steve,

The following is the most simple siphon I could come up with which consists of 1" PVC. It utilizes an 90 deg elbow and a street elbow ( a street elbow has one male end and one female end). As you can see in the picture it is 5/16" (8mm) off the floor of the grow bed and uses a grow basket as a strainer to keep the media away. I used a step-drill to make two 1-3/8 holes for the pipe. It is installed in a 4ft x 4ft x 13" reservoir which can hold 55 gallons, but once filled with Hydroton, it fills up with just 12.5 gallons, each cycle. This is about the same size as what you describe. I did buy 10 ft lengths of 2" and 3" dia PVC and all the other trappings described to make a bell siphon, but after analyzing the physics of it all, I said nuts to it, took everything back to Home Depot, and made the one you see.

Farmers irrigate their fields from a ditch, over a berm, using a similar system. It does require some tuning of the pump flow so a bypass valve is installed on the feed to restrict the flow from my 550 gph pump to about 50%, 6 ft below. It cycles about 4 times an hour. It drains in 3 minutes. You have to buy all these fittings anyway as part of making a bell siphon, so go ahead and try this first. Its cheap and seems to be reliable (so far). I did not use any glue, so it is just pressed togather, so I can take it apart if I need to change the height or anything.

The bypass pipe supplies aeration back to the fish tank through a bunch of 1/8" holes spaced about 1/4" apart..

More pictures upon request

Permalink Reply by Lonny Harper on May 17, 2011 at 11:51pm

Mike, how long have you been using this siphon. Has it required on going adjustments with plant growth?

Permalink Reply by steve on May 19, 2011 at 6:48am

Mike that's great, an engineer that went with the most simple method. We have gotten our world in a mess with engineers going the other way on this. I first had this type of siphon in mind, seems foolproof. Then the more I studied the more complicated it all sounded. I heard these siphons did not want to work properly or consistently, or any other for that matter? I have since built 2 tanks with my version of Affnan siphon. I will have a fairly heavy flow with larger pond so stepped it up a bit. I heated 1 1/4" tube and flared them to 2", made the bell then drilled 300 holes in a 4" tube for strainer. Even after I saw Chris made saw cuts in his strainer, which I may try next. This siphon started ok after I tweeked the exit pipe to restrain flow slightly with an elbow. I saw on you tube one man inserted a small piece of rubber tube inside drain pipe to slightly restrict flow to start siphon. I have at least 13 more tanks to build so would really like to have something consistent and easy. Would like to try Mikes design. Maybe someday we'll have a couple excellent foolproof options for people. Thanks All!!

Permalink Reply by Mike Konshak on May 19, 2011 at 4:26pm

Lonny, Keep in mind I'm a rookie at AP (but not pumps, head loss and flow), and at this time I am still waiting for my system to cycle, but it has been continuously operating for over a month like Old Faithful. I chose a basket that has openings that are smaller than the smallest Hydroton clay ball and sufficient in number to not restrict the water seeping into the basket even if roots begin to clog some of them. In essence the minimum opening required is the cross sectional area of the siphon, but that is an absolute minimum that does not account for muck to build up.Since I do not have a long experience with this, you should take my research with a grain of salt. Current performance is no indicator of future results. :o)

Lonny Harper said:

Mike, how long have you been using this siphon. Has it required on going adjustments with plant growth?