tank emptying problem

[patrick mccarthy]

hi i was hoping somebody could help me . i created a tank for my grow bed , i bought a small aquarium pump at wallmart and i created a bell siphon for the tank at the grow bed . it looks like my problem is water is emptying out of the tank at the same speed its coming in so it wont trip off my bell siphon to empty the tank . all i get is an even tank of water which is just below the level to trip the bell siphon . any hints would be great .

[Bob Terrell]

If your inflow is the same as your outflow you will not get the bell to work. Slowm your inflow down just a bit.

[Janice Lichti]

Hi Bob.... if you have not sufficiently rectified your bell siphon problem, I found that the downpipe piece should be a curved PVC back into the fish tank, that helped the siphon action! Ciou

Bob Terrell said:

If your inflow is the same as your outflow you will not get the bell to work. Slowm your inflow down just a bit.

[jim mckee]

I have quite a few grow beds so this may not apply to you since you only have 1 siphon to deal with.

I said BY BY to the bell siphon and drilled a hole at the bottom of the stand pipe at the lowest point on the pipe inside the grow bed.  I put the pump on a timer (saves a little $ once the timer is paid off).

5min pump time to fill the grow bed then pump shuts off .  Bed is draining.  My timer is set for 1hr off, 5min on.

jim

[Bob Campbell]

I agree with Jim.  Timed Flood and Drain is the way to go.

[Janice Lichti]

That's an amazing idea, I may use that for another bed I build.... thanks.  Yes, the inflow/outflow is a little tricky, I just use the shut off valve to regulate the flow to slower in and faster out once the siphon kicks in....

jim mckee said:

I have quite a few grow beds so this may not apply to you since you only have 1 siphon to deal with.

I said BY BY to the bell siphon and drilled a hole at the bottom of the stand pipe at the lowest point on the pipe inside the grow bed.  I put the pump on a timer (saves a little $ once the timer is paid off).

5min pump time to fill the grow bed then pump shuts off .  Bed is draining.  My timer is set for 1hr off, 5min on.

jim

[John]

Bell siphons are reliable for me "once" they are working reliably.  :)      It takes some fiddling sometimes w/ the siphon.    What you have is equilibrium.    A couple of things I would check:

.  1)  Check your outflow.   Make sure it has a decent vertical drop before and bend.   Depending on your pipe size, at least 6" works best for me.   I use 3/4" pipes.    Some day 45 degree bends work just fine but I find that 90 degree elbows are better in the drain out.  

2)  Try is increasing the water flow into the tank.  That is tricky in my setup because too much flow into the fish tank and it won't drain out quick enough into the beds so the fish tank can overflow.   So, push as much water into the FT as will drain out OK.    

3) So, those two things out of the way and it's still not working, try a longer pipe after the elbow in the drain.  That has got me out of equilibrium before.  Something about this guy Bernoulli.  Can't understand a word he says but his siphons never fail. 

4) Make sure you have water incoming through the media guard the lowest level. I cut more holes in the bottom than the top.   I put the guard in upside down once and could not get the siphon to kick.  Flipped it over, and it was fine. 

5) Lastly, it could be your bell.  Make sure it is airtight and has good inflow at the bottom.   Some people put that little hose on top to ensure the siphon kicks off when at lowest water level but that is not your issue and I have never needed that. 

My siphons are based on Meg Stout's design that I found at:   

http://365aquaponics.blogspot.com/2011/09/bell-siphon-parts-list.html