Backyard Aquaponics
A place to discuss aquaponics

Hi all,

I am wondering about the considerations for growing my veggies inside the fish tank...

In the 70's the New Alchemy Institute did some research I came across and from the pictures it seems their system was functioning well... They do not share the implications on how to feed the fish and recirculate the water...

Has anyone got experience with such a single container system, or thoughts why it might not work... Or conversely why it might be a great way to do it...

Thank in advance!

All depends on if the fish are gonna kill off your veggies by eating the roots or not.

Think of it this way. Any well balanced ornamental pond that has fish, plants and some form of filtration where water changes are not constantly needed, is in a way, a form of Aquaponics. Usually lightly stocked with a few goldfish or something and pond plants, some form of filter and or filter/waterfall and it all just kinda works.

When you start trying to grow larger numbers of fish, they are more likely to do damage to the plants (especially if they eat them or try to churn up the root area to spawn.) And also, with more fish, there is usually more need for filtration. Even if you manage to grow the plants right in the tank with the fish, you probably still need a separate bio-filter.

Probably the main reasons not to grow the plants right in with the fish is aeration and support. Some plants might be quite happy growing right in the water and be able to support themselves. Most veggies though, need support and they need more air to their roots than they will get if submerged in a fish tank.

This is not to say it can't be done, we know it can.
This method would just require looking at the needs of all aspects involved and making sure all needs are addressed.
Fish need space, water, aeration, feed, solids and bio-filtration
Bio-filter needs, surface area, water, aeration, and fish waste
Plants need, support, water, aeration, light, solids and bio-filtration

Most of us here are used to the grow beds supplying space/support for plants as well as covering the solids filtration and bio-filtration needs for both the plants and the fish. If the grow beds are media filled flood and drain beds, they manage this without requiring additional air blowers being provided to the beds.

to add to TC's comments, plants generally only take out nitrates, and fish produce ammonia. AP uses bacteria to convert ammonia to nitrites then nitrates for the plants to use. You would need somewhere for the bacteria to live (gravel, bioballs, clay balls etc), which is what TC is referring to as the biofilter. In theory this can be in the tank as well.

In theory it could.... but the level of biofiltraion provided by any raft floating on top of the tank.... with or without media filled pots.... would be minimal....

And then you have the build and disposal of solids to deal with....

The alchemy system would only have worked with regular water changes... like an aquarium...

IMO... it just wouldn't be worth the effort... as a standalone system anyway...