Hi Phil.
There are a few aquaponics threads that you could peruse that will have answers to your questions.
The big issue, though, is that if you are producing
enough fish to eat as a
staple for two adults, the amount of fertilizer you generate will probably far outweigh the amount you need to grow the veg you two would need.
Realistically, you are starting with fingerlings, in all likelihood, right? You won't need more than one IBC tote for them at that stage. I would base your fish space based not on stocking rates, but on the amount of space an individual juvenile to adult needs.
To
answer your questions, I have a few of my own that
should help you arrive at a more complete large picture.
How many species of fish/organism will you/can you fit in the space? For me, I would be looking to construct as complete an ecosystem analogue as possible, making sure that there are oxygen-creating aquatic plants that also provide food and
shelter to smaller fish; a species such as the White Cloud Mountain Minnow, something small and fairly hardy that would convert small particulates into food, and become food for a larger species of fish; an edible catfish species, dwelling in the bottom of the tank and eating whatever falls to them; probably algae-eating fish or snails that could likewise serve as a food source; and a barrel sedimentation tank holding a species of bivalve suitable for my needs, for
water filtration and another protein source.
All this would provide natural,
sustainable, short-term backups for any equipment involved for oxygenation, cleaning, and filtration, such that the negative effects of a power outage would be minimised. I would definitely have a raised reservoir as a "water battery" of sorts, such that if the power went out, there would be a reserve of water pouring gently into the tank, adding oxygen for that little bit longer until you can get the power up again. But the potential for equipment failure wouldn't keep me from adding oxygen to the system mechanically anyways, as along with food, oxygen will be the limiting factor to the system.
What form do you see your aquaponics taking? Are you going to be growing greens on floating rafts in the IBC totes where your fish live? Are you cycling dirty fish water out of your tanks and into a flood-and-drain
bucket system, or one of those constant flow systems, whereby plants are grown in some neutral growing medium in a connected pipe system, gravity fed on racks or something? Are you looking at simply watering planted beds with fish water? Or some combination of the above?
And what other farm/food systems are going to be interacting with your aquaponic set up? Some who keep aquaponic setups, even passive
pond setups, grow things like duckweed or other edible plants for ducks or
chickens to eat, and there are types of algae that can be harvested and dried, to be either added as an amendment to the soil or added to animal
feed.
The point is, more detail is better. Also, the more you think about how the waste products of your aquaponic adventures can be used as feedstock for other systems, the more useful the whole idea becomes.
But let us know what happens, and good luck.
-CK
A human being should be able to change a diaper, plan an invasion, butcher a hog, conn a ship, design a building, write a sonnet, balance accounts, build a wall, set a bone, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, analyze a new problem, pitch manure, program a computer, cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects.
-Robert A. Heinlein
