Bell Siphon Problem. HELP!!

[james davis]

Hello all. I recently started my first aquaponics system and im having a problem with my bell siphon. It will seem to be working perfectly buy after filling the grow bed up the siphon wont start. It will just drain down the inside pipe until i move the outside of the bell a little maybe turning it a quarter inch then the siphon will start. it will then ususlly work for a few cycles untill stoping at the same part again. i know you all have lots of experience with aquaponics so any help would be appreciated. thanks.

[Chris Griggs]

Do agree... increasing flow rate will help start siphon or increasing headflow will help if the auto siphon is the choice.

[Jim Fisk]

How can we help James if we have no details as to how his is made? One picture or drawing and we can help. I have limited time to discuss theory. I can tell in about 2 seconds if it is poor flow or poor design. I need the facts.

@Rob. As you must know by now my GBs are IBCs.12" deep media but I keep 3 sizes of siphons in stock that all work great and are all tested with various flow rates and are designed for barrelponics, small grow trays and IBCs. Again I need a little more description than "my bell siphon" in order to help. I have seen so many convoluted, ridiculous, complicated designs with "snorkels" "traps", etc. that there is no such thing as "a bell siphon". Mine follow the Affnan KISS principle but with simple engineering and they work. I help anyone at no charge, even blind folks near you who's system is now working flawlessly btw after they spent all sorts of money on other peoples "commercial" siphons. I can build any size for any size GB.

@Chris G. I show anyone for free how to fix their siphon. My biggest one (IBC) costs less than 10.00 in parts including a kick ass gravel guard. If they have more than one GB the timer/sequencing valve issue gets a whole lot more complicated than siphons if that siphon is designed properly and that can only be determined by testing unless it is a proven design that is duplicated exactly. I will help anyone for free and do it all the time so save the lecture for those charging BIG bucks to help build systems.

[Chris Griggs]

Once again. I am trying to help James get his system working too so he can actually enjoy it instead of being a pain in the butt. He has a single grow bed. So none of the other issues apply in this case. I have both timers and autosiphons on separate units. Not once had issue with flood n drain on timer. Yet have them often with my autosiphon. That is MY experience. FREE to share. Isn't that the point of this forum after all?? But apparently its OK to lecture others about your amazing skills at cutting PVC pipe? It isn't rocket science... Don't break your arm patting yourself on the back! Many ways to skin a cat!

[Jim Fisk]

Show me your siphon design and I can help you too Chris. No charge. Apparently there is a bit more to it than cutting PVC pipe. Yours are living proof apparently. I fix bad designs for people all the time. Happy to help. I still see no details on James design so I cannot help him until I see what he has. I have spent years in industry correcting bad engineering so these siphons are a hoot. Snide remarks aside. I have helped close to 300 people all over the world now so forgive my confidence.

Chris Griggs said:

Once again. I am trying to help James get his system working too so he can actually enjoy it instead of being a pain in the butt. He has a single grow bed. So none of the other issues apply in this case. I have both timers and autosiphons on separate units. Not once had issue with flood n drain on timer. Yet have them often with my autosiphon. That is MY experience. FREE to share. Isn't that the point of this forum after all?? But apparently its OK to lecture others about your amazing skills at cutting PVC pipe? It isn't rocket science... Don't break your arm patting yourself on the back! Many ways to skin a cat!

[Chris Griggs]

That is nice of you. I have actually removed the only big one i had on a 4×4 growbed and went to timers on 3 of my units. Determined to play with a siphon and figure them out, I have a 55 gallon barrel cut in half on top of a barrel just for a breeding tank and lettuce bed. My flow rate is extremely low because the bed is small. After MANY attempts and mods, it has finally worked for almost a month now with no issues. I too did a fair amount of research on them. I am a contractor by trade and a tinkerer by nature. Autospihons fascinate me! They are Ingenious! Never questioned that. But I feel his pain in trying to get them right. I chose to build all my units and projects myself. Just the way I am. I am sure you are proud of the work and help you have put into them and others. That's great you have done that! I was just trying to help sharing my experience, same as you. I'd be more interested in your heat exchanger for me personally! I'm having water temp issues! Lol No disrespect meant at any time!

[Jim Fisk]

Thanks Chris for toning it down. I get tired of the attacks on bell siphons not to mention me. What the H happened to James??? Hello, calling James. One pic is all we need. I just found it funny that he wanted help with his siphon and every one with a few exceptions told him to change everything to a whole other method instead of fixing his siphon.

Anyway, same deal. I need details of your heating problem and we should probably start by getting it off of this thread. We have a thread going on that HERE.

[Benjamin Wasserstein]

Rob,

 

I'm curious though, how is the solids build-up lessened to any extent by using a timed pump and basic drain? It seems to me that maintenance is required for any aquaculture set-up. Pipes need to be cleaned more-so when there is no solids filtration involved in a system (e.g., a settling basin), and design should always account for maintenance and cleaning (e.g., union joints on pipes for access to straight sections for maintenance). The plaque build-up you mention is a result of the amount of fish waste produced and the amount of feed that goes uneaten, rather than a result of the type of drain used...

 Fact is, dealing with timed pumps can lead to serious problems - a pump goes out and a tank of fish near harvest can easily suffer from ammonia toxicity because that water isn't being passed through your biofilter. There goes your product overnight. Granted, this can happen to any pump, but when it's being switched on and off hourly the chance of the motor blowing out has got to be higher. There's nothing wrong with bell siphons. Just consider Bernoulli's equation and a 3:1 ratio of outer pipe to standpipe ratio when designing venturi drains. The 2:1 venturi attachment at the top of the stand pipe is key, as mentioned. Bigger beds will obviously have larger piping to account for the increased volume of water that needs to be drained, but the concept remains the same.

 

All that needs to happen is for the drain pipe to fill with water as far as James should be concerned. This will start the venturi drain. Rather the drain pipe is trickling water - his autosiphon is close to working! Increased head loss or increased inflow will fix the problem - no need to completely change up design here...adding a couple 90' fittings would probably be his cheapest fix. Alternatively, he could use smaller diameter pvc on his drains or increase velocity of flow into the bed by using a pump with a higher gph rating.

 

Cheers,

 

Benjamin Wasserstein

 

P.S. - Really do like your greenhouse, Rob!

Rob Nash said:

Hi James.. this is why bell siphons are on their way out.. go with the old hydroponic standard, and use a timer and perforated standpipe. it works every time.
I could offer plans and how-to's for siphons for any size bed and pump combo.. but once your plants get well rooted, worm poops build up, and pipes get a plaque lining in them, the water flow changes and your left with a siphon that wont work. IMO - these are for folks that don't have access to a good timer..
toss the bell, drill four 1/4" holes in the very bottom of your stand pipe, set your timer... be done, have fun.

Cheers,
Rob

[Jim Fisk]

Right on Benjamin.

Not sure where you get the 3-1 tho.

A 1" standpipe should have a 2" funnel on top. Then 2 90's below as you state. Never ever fails to trigger AND break siphon over a wide range of flow. The advice I read here of just more flow could easily cause it not to break in many cases. The only redo I run into when helping someone fix a bad design by adding the funnel top is that generally that will mean also replacing the bell so it will fit over the new funnel and of course that might trigger a bigger gravel guard.

The other strange thing I see a lot of is a 6" gravel guard so they can reach in and pull the bell. That's why mine have a nifty looking porcelain knob on top but you must replace the knob screw with a ss screw or troubles down the road. I am very stingy with grow space and by using the knob an IBC GB size siphon with a 2" funnel fits in a 3" bell which fits in a 4" gravel guard. So simple. So pain free. I use the cheaper S&D pipe as that has quite a bit more volume for less money and since I ship them all over the planet it cuts postage right about in half as well, so win, win. Even the 4" GG is S&D. Here's the whole story in a pic: Total cost under 10.00. Colors vary:-)

[Rob Nash]

real quick.. i have an hour long drive to the system im installing this week, but will try to clear up my opinion...

Jim - not attacking your efforts, but when you graduate beyond ibc sized beds, you will learn that bells dont do the job as well as a standpipe.  and like i said, i could go on and on about how to build them to work, in fact i have posted a formula that works flawlessly, and perhaps should have just directed James to that link, but dont care for siphons due to the fact that when i install a system for someone, i like the idea of not having to trouble shoot them later.... oh, and they dont work on the 5ft x 12 ft beds i build. .. they will drain half the bed then start over, with out draining the far end all the way.

Ben - your correct, using a standpipe doesn't change the rate of solid build up, it just doesnt have to become an issue when it does.   they work regardless.   as for the timer being a problem if the pump doesnt work and killing your fish over night.. you may be over thinking that one a bit... i have never had that happen, even in a 1000 gallon tank with 500lbs of fish in it. ive gone 5 days without running a pump in that tank.

this is my opinion on bell siphons.. i dont use them.   some folks like the idea of tinkering with them, this i understand, been there, done that... but dont see the point in installing them in a system for a customer, if there is an option.

ps- the argument regarding timers killing pumps is a little off... electric motors (with winding, brushes etc.) will burn out when turned on and off too often,,, mag drive pumps, are not the electric motors... i have pumps from 400gph to 3600gph that have run on timers for more 4-5 years. 

[Alex Veidel]

That's really good to know Rob. Seems consistent with everything I've seen so far....I noticed that commercial systems using bell siphons often divide their large growbeds into multiple, smaller sections, each with their own siphon.

Rob Nash said:

to Jim.. I want to add that my opinion of bell siphons is based mostly on large grow beds. 4ft x 8ft and up... siphons do a great job on small beds.. FTR- I have 3 that have been running for 3-4 years without fail.. all of them are on small growbeds.. 4x4 or less.

so I ask... what size beds are you using them on?

[Alex Veidel]

Oh wait, are you the guy that makes/sells those siphons? I've seen them around the internet from time to time. Are you using a mill to make 'em? 'Cause those air-brake teeth and the slots in your media guard look pretty sweet.... :) 

Jim Fisk said:

Right on Benjamin.

Not sure where you get the 3-1 tho.

A 1" standpipe should have a 2" funnel on top. Then 2 90's below as you state. Never ever fails to trigger AND break siphon over a wide range of flow. The advice I read here of just more flow could easily cause it not to break in many cases. The only redo I run into when helping someone fix a bad design by adding the funnel top is that generally that will mean also replacing the bell so it will fit over the new funnel and of course that might trigger a bigger gravel guard.

The other strange thing I see a lot of is a 6" gravel guard so they can reach in and pull the bell. That's why mine have a nifty looking porcelain knob on top but you must replace the knob screw with a ss screw or troubles down the road. I am very stingy with grow space and by using the knob an IBC GB size siphon with a 2" funnel fits in a 3" bell which fits in a 4" gravel guard. So simple. So pain free. I use the cheaper S&D pipe as that has quite a bit more volume for less money and since I ship them all over the planet it cuts postage right about in half as well, so win, win. Even the 4" GG is S&D. Here's the whole story in a pic: Total cost under 10.00. Colors vary:-)

[Rob Nash]

not to mention the cost... if you build a siphon, you could spend over 50$ just in parts. then you have to manufacture it,, time = $ , a timer cost about $50... stand pipes are just a 10 inch piece of pvc.