2in bell siphon not working

reese77

My flood table was filling faster than my previous 3/4in bell siphon could empty to I moved up to a 2in siphon but I cannot get the suction to start. I tried with a clear glass so I could watch the air get removed and the suction start but there was always a air bubble left in the glass and the removal or air never completed. There was only a 1/2in gap between the top of the drain pipe and the roof of the cup. I created a 3in bell with a pvc cap and it is air tight and only 1/2-3/4in above the drain pipe inlet but still no luck. I need my table to drain fast or I need to change from using a flood table to a NFT. Ideas? Pics below.

helomech

Try the afnan style siphon. All of mine work perfectly. I am using 1" line with a 2" adapter on the top, and 4 of them are able to handle 2000 gallons per hour of water flow.

reese77

helomech wrote:

Try the afnan style siphon. All of mine work perfectly. I am using 1" line with a 2" adapter on the top, and 4 of them are able to handle 2000 gallons per hour of water flow.

2000GPH Wow!

So the only difference is that I will have a smaller pipe with a large opening at top like a funnel? Do you have a link to your post with pictures of this?

helomech

yeah, just a larger opening so that the water speeds up as it enters the smaller pipe. You can dig through my thread it is at the bottom of my posts, or you can do a search on youtube for afnan siphon.

reese77

I got a U siphon working really well but I now need a larger sump tank and stronger sump pump so the sump tank can empty before overflowing. I have a float switch tied to my pump but it switches on late. I modified how it is zip tied down so it will come on when the as soon as water is above the pump but it is quirky. I am going to return to Home Depot and find another float switch online. I need to add a U siphon to my other table as well.

Question: Does anyone have their aquaponics system on a timer or is it always constant flow? I see some of the IBC systems on youtube on timers but just wondering what the preference is.

Mr Damage

Hi Reese,

Quote:

My flood table was filling faster than my previous 3/4in bell siphon could empty to I moved up to a 2in siphon but I cannot get the suction to start. I tried with a clear glass so I could watch the air get removed and the suction start but there was always a air bubble left in the glass and the removal or air never completed. There was only a 1/2in gap between the top of the drain pipe and the roof of the cup. I created a 3in bell with a pvc cap and it is air tight and only 1/2-3/4in above the drain pipe inlet but still no luck. I need my table to drain fast or I need to change from using a flood table to a NFT. Ideas? Pics below.

I think the problem with your initial 3/4" design not working wasn't because of insufficient standpipe diameter... it was simply a case of too much flow. The system you can see in my avatar pic consisted of an 1160 x 1160 x 120mm (45" x 45" x 4¾") flood and tray fitted with a bell siphon comprising a 65mm (2.5") dia bell and 15mm (5/8") dia standpipe.

The GB flooded to about 80mm (3") in 10-11 minutes and drained in under a minute, followed by about 30 secs of gurgling etc before the siphon broke suction completely. All up the entire F&D cycle took about 12 minutes.

I currently make bell siphon kits for GB's up to 300L capacity and 300mm depth that utilise a 15mm (5/8") dia standpipe and work perfectly fine, for a 300L GB the F&D cycle in most cases is around 23-27 minutes. If fitted with a 20mm (3/4") standpipe the F&D cycle on a 300L GB comes down to around the 15-17 min mark.

The largest siphon kit I make will operate well in GB's up to 1000L in capacity... and it only utilises a 25mm (1") standpipe, in fact I fitted one of them to a 1200L GB and it works fine, except the F&D cycle is out to nearly 40 mins, which is getting a bit long IMO.

Long story short, I think you just needed to slow the flow down in your 3/4" design... and you well and truly oversized your standpipe in your 2" design. You would need a MASSIVE flow rate to get a siphon with 2" dia standpipe to start flowing.

Also, the small "castellated" cut-outs in the base of the bell would have been limiting the flow, especially for the 2" standpipe.

Just some thoughts.

Cheers.

reese77

Thanks for the feedback Mr. Damage. My 2'x4' table fills up to 3.5" in about 2 minutes. My pump is 633GPH. I was testing with only filling one tray but I plan to have 4, all coming off of the the one tank/pump. I am getting rid of my second 250Gal tank and instead of using it for more fish, I will cut in half and use this as the sump tank. Another option is to get a smaller pump.

I think I will be fine once I have a larger sump tank but I still do not want to have my system constantly running and would like to have it on a time but I will research what others are doing.

Charlie

reese77 wrote:

Question: Does anyone have their aquaponics system on a timer or is it always constant flow? I see some of the IBC systems on youtube on timers but just wondering what the preference is.

There are many systems out there on timed flood and drain.

DrLuke

:raisehand: I switch my small system between timed flood and drain and constant flood all the time.

reese77

DrLuke wrote:

:raisehand: I switch my small system between timed flood and drain and constant flood all the time.

Cool. What kind of on/off intervals do you use and with timed do you find the ammonia levels in the fish tank to be fine or do they spike and then you switch to constant?

DrLuke

Yeah. The timer is in 15-15 cycle. If I spike ammonia or something I switch it to constant flood for a few days. Also some plants seem to like the CF better than the F&D so I just watch them and switch back and forward when I think something is struggling.

It's not like I spike the ammonia often, the f&d is perfectly adequate with filtration

Okin23

Hi Reese. I would also think of a thinner standpipe and a afnan-style opening. This siphons worked best with my tests. It also looks like there is not much spave between the fitting and the siphons teeth - maybe you can make the teeth bigger and add some holes?

At the moment i have a miniature system (35 L Water, 1 balkony-flower-box holding 6 L) with very thin hoses and pipes and i only got my bell siphon working with an afnan-standpipe. In this size it is very difficult to "calibrate" the flow and the drain, but it´s possible. Since the system stands on my balcony and the suction of the siphon is a bit loud, i have my system timed to run from 7 a.m. to 10 p.m. (draining every 3 minutes) and pause during the night. I will change the system to a timed constant flow (which is not so noisy) and have my timer 15 on/45 off, holding this rythm 24/7. Plants are growing VERY well and the fish are happy and active.

Greetings from austria!

reese77

I am going with the u siphon, it drains my table as desired. I am doing a complete re-config. I removed my 2 250Gal IBC totes and now have my fish in a 300Gal Rubbermaid Aquaculture tote. It was hard as crap trying to catch all 100 fish but none loss, none have died so far. This tank is lower so I can drain my beds right into it, totally removing the sump from the equation.

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