Backyard Aquaponics
A place to discuss aquaponics

Hi guys,

I'm trying to design a small indoor system. The basic components would include the following:
- 50 gallon fish tank with aerator
- 60 sq. ft. growing area (grow bed and vertical towers)
- Worms in the grow bed for solids breakdown

First and foremost, do you think this ratio would work out? I know it's generally recommended to have 0.5-1lb of fish per sq. ft. of growing space. This works out to at least 30 lbs of fish in 50 gallons of water, which seems to be extremely dense. Would I be okay stocking fish to a lower density, and if so would you recommend using the grow bed only (and take out the vertical towers)?

Second, what kind of fish would you recommend for this type of system? I'm not looking to eat our fish, and so I was initially thinking koi but it looks like they'll outgrow the tank extremely quickly. Would guppies be a viable option, and if so how densely can I stock them in a 50 gallon tank?

Third, I'm thinking of having worms in the grow bed. Would the worms + grow media be enough for solids filtration? Or would you recommend an additional filter, e.g. a swirl or radial filter?

Lastly, if my priority is plant (veggies) production, would you recommend I just go for a bigger fish tank? A bigger tank would not fit within my space limitations, but I might be able to push it to 70 gallons.

Thanks in advance for any guidance.

That would be way too many fish for the volume of water - Yes you can stock much lighter and will do fine. After your system is cycled you can supplement with something like blood and bone meal which will breakdown slowly (but you might not need to anyway). Aside from the filtration recommendation I think the other recommendation is 1 lb of fish per 2.5 to 5 gallons of water

http://www.backyardaquaponics.com/forum/viewtopic.php?f=12&t=6646

Personally I'd skip the towers for now and just use the grow beds. You could probably get this to work with guppies but I'm not sure what to suggest for feed or stocking density since most flake food isn't very good at providing what the plants need so we usually recommend a commercial pellet (flakes seem to be more geared toward maintenance and color but not growth of fish). There are plenty of options if you're going to heat the aquarium or you could, if it's legal use bluegill. Bluegill grow fairly slow but can be pellet trained and will eat enough to grow the plants pretty well.

As far as the filter - I can't see you needing another filter at this time. Your grow bed is almost 10 times the size of your tank in volume. You could go for years with a moderate stocking density before the grow bed needed to be cleaned. Using an RFF removes some of the solids that would otherwise breakdown in the grow bed and provide nutrients for the plants and I think you'll probably need those in this system. The RFF also adds maintenance and is probably just overkill in this case.

I don't think the difference between a 50 and 70 gallon tank would be enough to warrant up-sizing the tank in this case but I'm not sure .