I am new to aquaponics and I would really appreciate some advice.
I am building a very small ebb-and-flow system (I know that is not gonna be very stable). I am using a 300 lt (79 gallons) bathtub as aquarium for the fish and 4 euro containers for food as grow beds, each one 72 lt (19 gallons). 1.Do you think that I should use a sump, or just pumping the water from the bathtube to the growbeds and from there back to the bathtube with gravity will work?
Moreover, I have problem with the siphon system. Here is a picture of what I made and didnt work (the output water is the same as input)
Reading this study, I realised that the pipe diameters I used are very big for my small grow-beds. 2.Is there a way that I can still make it work? Or should I find bigger grow beds or smaller standpipe+bell?
3. I didn't use a snorkel. Is that necessary?
I m looking forward to your answers. Thank you!
If the inflow is only causing the water to trickle over the top of the siphon but not kick in, it means your inflow to the bed is too slow, you may need a bigger pump or a smaller siphon
You are kinda on the edge of needing a sump since you have almost equal grow bed to fish tank. If your amount of fish will be kept minimal and they don't mind shallow water you might be ok but some larger fish are going to be quite stressed by that kind of water level fluctuation.
However, there is the option of simply removing the bell of the siphon on a bed or two and running them constant flood, this would result in less water level fluctuation and also probably be less work replacing siphon parts to get the other beds to balance out and do the flood and drain thing properly.
The snorkel tube is generally not needed for an affnan siphon and would not be a help in getting the siphon to start anyway, the snorkel is used to help a siphon stop when it's having trouble getting a good gulp of air to cut out once the bed is mostly drained.
I just recently set up my first system and had to play with getting the siphoning right. I used 1 inch pvc without a funnel, and it works well with a 60 gal/hr pump.
The first two things I would consider is make sure you have ample flow into the bell housing.
If you have to redesign to reduce the pipe size, probably it will prabably be easier to put some sort of restrictor plate or orfice into the bottom of the funnel as opposed to changing the whole thing out.
I have seen several recomendations online that the funnel mouth should be twice the diameter of the standpipe. Again I am not using a funnel at all.
Good luck and be patient.
Thank you both guys for your replies.
All your ideas sound good. I will try first with a restrictor plate into the bottom of the funnel - that seems the easiest- to see how that goes.I will also check if I can find some second-hand bigger growbeds, maybe that would solve the problem as well.
I would like to grow Tilapia for eating, so I guess I am gonna need the sump.
I m gonna let you know!
Many thanks again
Thank you all for the advices, I got the siphon working!
I have placed a smaller pipe (20 mm) with the help of a restrictor at the bottom of the funnel. It works perfectly!