Since I will be using an overflow box to provide water for the grow bed, will it give out proper nutrients to the plants? My growbed bell siphon returns to the bottom of the fish tank as well which I expect would help with rotation of fish water.
Two other questions as well, should an under gravel filter be considered since the larger chunks of fish waste probably won't exit the tank via the overflow box? And what are all the nutrients plants take from the fish water, is it just nitrates and water?
I have about a 1'x2'x7"(LxWxH) grow bed, a 10 gallon tank, and a sump tank.
How the water cycles through the system:
Growbed "bell siphons" to fish tank below, the fish tank "overflows" into the sump tank below, and the sump tank has a water pump returning the water into the grow bed on top.
I am new to aquaponics by the way, this is actually my first post on the forums. I just received the "Aquaponic Gardening" book in the mail today which I plan to read up on to improve and key in my aquaponics table.
I don't know exactly what your setup looks like, but if you extend your overflow box to the bottom of the fishtank, you'll be able to get at those settling solids.
Speaking only from my experience with a very similar system (see video at https://www.youtube.com/watch?v=R-QSVILv9gI), regardless of whether the tank overflow is at the top or bottom, some of the fish waste will settle either in the tank or in the sump. You'll just need to scoop it up with a net every few days. No big deal.