bell siphon floating

[Lyle]

I am putting together a medium size system in my yard and an running into problems with the media beds bell siphon.  I have had a smaller system running for a year and a half and have not had any problems with the siphon which makes this even more frustrating.

basically the bell is floating in the water and not getting pulled down and i can not figure out why.  I have tried different size stand pipes and bells and nothing seems to be helping. I have even taken out the stand pipe and siphon in my running media bed and tried that in the new beds and it still floats

the new beds are the tops of IBC totes(about 40"x48"x16"deep) and are run in a series of 3 and I have a trap under each bed.  here is a pic of the beds

here is a pic of the bells and stand pipes i have tried, on top the bells are 3" and 2" and the stand pipes are 3/4 with a 1" coupling and a straight 3/4" pipe,  the bulkhead is 3/4".  below is the bell and stand pipe that have been running in my smaller system(the bed is 26"x84"x12"deep

I have not yet put a breathing tube on the test bells but i am using a small 1/4" tube on the bell that is running.

any help would be greatly appreciated

[Alex Veidel]

Hmm, that doesn't make sense to me....why would it float? The standpipe should be letting air in and out of the bell until it triggers....Are you using schedule 40 pvc?

[Lyle]

Yes, everything is Sch 40. 

my first thought was that it had something to do with it being in a series, so  I added the trap under each bed. I got the idea of the trap from Rob Torcellini's youtube channel so i can imagine that the trap is causing the problem. My other thought is that the standpipe/bell are in the middle of the tote in the cap.  with the cap being at a lower height then the bottom of the rest of the bed, but i cant see how that would cause this, however i cant think of what else is different then my siphon that works.

[Alex Veidel]

Wait, is the top of your bell lower than the water level in your growbed?

[Lyle]

The bells are just over 16" and the bed is about 16" and then the depth of the cap adds about an inch. When i put the bell in wit no water and fill up the bed the bell will float up just a little. But when the bed is about half or more full and I put the bell in it floats like a fishing bobber.

The bell on my running system will get pulled down even when the bed is almost full(this bed is only 12" deep with a bell that is about 12"

[Lyle]

So I have been playing with it and I figured out what the problem is.  The drain pipe had a 20' run to get to the sump tank, as soon as i shortened that length the bell was pulled down just like it should be. 

So I was wondering if anyone else has a bell siphon running with a long drain line and how they have it set up. 

Mine that is not working is 3/4" pipe with a trap(although it is possible the trap is not air tight since i did not have it glued)  running a total length of 20'.  It is also three beds running in a series as can be seen from my first pic.

also thanks Alex for the initial replies

[Steve R]

is the output of the bell submerged?

[Alex Veidel]

Ah, excellent question Steve :)

Lyle, air needs to be able to get into your bell through your standpipe until the growbed is ready to siphon.

Steve R said:

is the output of the bell submerged?

[Steve R]

Every bell iv seen that floated was because there was no way for air to enter the siphon. You can easily fix this by drilling a few air holes in the output where the water returns to your tank. You can Swiss cheese it( Drill it full of random holes) to make a silencer i did that to the system thats inside my house and it reduced the noise dramatically.. 

Alex Veidel said:

Ah, excellent question Steve :)

Lyle, air needs to be able to get into your bell through your standpipe until the growbed is ready to siphon.

Steve R said:

is the output of the bell submerged?

[Lyle]

The output is not submerged, it lets out above the sump tank.    Do you think having such a long line with only 3/4" pipe could be restricting the air going up into the bell? 

Since i have gotten the first bed cycling it is draining slower then I would like and i am thinking of increasing the pipe size to 1"  and now I am wondering if this change could also help the bell problem

[Nadeem Hydal]

It would be better for you to keep the 3/4 drain short as possible and let it drain into a larger drain pipe that takes the water back to the sump/ft. Looking at the setup above I would have one straight 4" or 3" drain that takes up the drains from the 3 grow beds.

[Jack Dunbar]

Being that his run to his drain tank is so long, is it pitched properly so no water gets trapped in it? I agree w/Nadeem.

[Rob Nash]

Nadeem has the right idea.. .go with a larger pipe. even 1-1/2" will do.. it has  to have air just bellow the bed to allow the siphon to interrupt itself.  dont glue it to the bed at all.. just let the bed's 3/4" tail pipe drain into the 1-1/2" 90 and then run to the FT   (so long as the fish tank is lower than the bottom of the growbeds.

...or ditch the bell siphon all together and add a timer and perforated stand pipe.