I have started cycling my first AP project today!
Here are my parameters:
- 25 gallon fish tank with a 3.8 cu ft grow bed
- Pea Gravel Media
- 400 g/h pump (3/4" PVC) 3.5' head from fish tank to grow bed
- Bell siphon drainage (1" PVC Bell)
- Media depth is ~11"
I have a couple of questions that hopefully some of you pros can answer.
1. After my siphon trips and the bed drains, it gets to a low level but won't shut off if the pump is running. Im thinking this is due to my high flow rate out of the pump or possibly there is too much space for inflow at the slits at the bottom of the bell part. Will anything about this change if my bed is completely filled with media as opposed to it being half filled as it is now?
2. Is it ok that there is 2.5" of water at the bottom of the grow bed after Bell shuts off or should there be less?
3. Does this setup seem more like it should be constantly pumping and draining or can I let it do its pump drain cycle in intervals thoughout the day?
Im pretty fired up about this AP thing and appreciate any help that's given. :)
1) Put a T in the line going to the grow bed from the pump with a ball valve returning some of the flow back to the fish tank, this way you can restrict the amount of water flowing to the growbed which will stop your siphon.
2) It could get anaerobic at that depth, but i'm not experience enough to know.
3) At least until you get the system up and cycled you should have constant pumping. I like to think of the entire AP system as a living organism on life support, it needs it's heart pumping and lungs breathing. Also most pumps are not meant to be turned on and off frequently. It could effect the longevity of the pump. Others will tell you it is fine to turn it on and off.
I watched your video on assembling your NYC aquaponics setup and it seems our system has some things in common. I'm definitely going to take your advice on putting a T in the pump line, and because its not much work or cost to replace the bell, I'll do that so i have only 1 inch of residual water. Your setup looks great, and I'm hoping I get similar results.
The T bypass with a valve back tot he fish tank is definitely a great way to adjust the water flow to the grow beds without burning up the pump to allow you to get the right flow balance for the siphons.
And once you finish filling the grow bed with media, it will help make the balancing easier. See when the water level is over the media at siphon start height, you actually need a faster flow to kick the siphon over but if the water level never comes over the media the proper flow rate should be better matched with a flow rate that will still let the siphon stop properly at the drained end of things.
However, if we are talking about barrels cut the long way, you have an even tighter margin of error since the changing volume of the barrel with the height will make balancing a siphon tricky.
Thanks guys for the advice. Got it cycling nicely now with no long waits for the siphon to kick on or off. It seemed after I took your advice to put a T on the pump with a ball valve and filled the grow bed with media, it was almost there. I made a small adjustment by increase the height of the bell over the drain and that made a tremendous difference, allowing the drain to take a bigger gulp when shutting off.
this is how I feel right now:Yes! I am invincible!