I purchased a used 20 gallon aquarium on craigslist this weekend and am planning to use it for my attempt at a locally sourced and mostly recycled window farm style aquaponics system. I’m planning on using a small pump I have on hand with a digital timer to create an ebb and flow system with the pump delivering fish water to a reservoir that drains through window farm like components (2L soda bottles, re-purposed container “net pots”, and hydroton) that drain back into the tank. I won’t be eating the fish but instead, plan to use guppies or another hearty tropical fish (that is fairly pH tolerant) to help beautify my living space. I’ll be using 6500K CFL bulbs for additional light sources for the plants and would like to try basil, spinach, strawberries, cilantro, and lettuce to see which works best for my system. At some point, I’d like to get a bit more adventurous and try tropicals such as coffee and lime, but that is down the road a bit. I’ll start my own thread once I start setting this up in earnest but what does everyone think? Does anyone have advice on water additives? I’m thinking that usual planted tank fertilizers should be alright for not harming the fish and also feeding the plants (in addition to the natural breakdown of ammonia from the fish).

Bevan, as I’ve said elsewhere, I do have an aquarium already up and running. It’s a 40 gallon breeder tank with a few anubias, a lot of java moss and a few other odds and ends and it’s been running in its current state for about 3 years – I also had it up for a couple years before I moved.
Taobass, guppies are hardy but they do best in a higher pH (>7.5) setup – also from my experience they breed like rabbits so you might want to consider that ahead of time especially with only 20 gallons. From what I’ve read, most plants one would grow in a window farm do better in a lower pH setup (<7) – anyone please feel free to correct me on this point as I'm just stating what I've read. If that is the case, you might want to consider tetras which are hardy (I have some black skirt tetras that are around 5 years old and have moved with me 4 times) and do well in lower pH environs. You could also do goldfish, eliminating the need for a heater, but with a 20 gallon tank, you would want to make sure you know how big the animals you get will grow – goldfish have high oxygen requirements and some grow large very quickly. Coffee might cause a severe pH swing in that quantity of water and also release caffeine and other chemicals which might stress your fish. I find that bogwood keeps my pH pretty consistently low (it slowly releases tannins) and, when I had guppies, crushed coral mixed into my regular substrate kept my pH consistently high – limestone should do the same.

Sounds awesome guys. Can you post some photos of your setup? I have a windowfarm going now and hope to get a 20 gal fish tank going by wintertime this year. For the tanks, do you have a traditional setup, or does it change when there is a windowfarm attached? thanks

I too would like to see some pictures of an aquaponics window garden if anyone has any.

hey elizabeth. i think its hard to say because i guess that there are not many of us out there yet. it also depends on what you are going to keep. for fish, a 10gallon tank would be the minimum, although there are some very small species like danio danio or some rasboras that can be kept in smaller tanks. with shrimp, for example cherry shrimp, you can even take 2 gallon tanks, but the amount of nutrients produces might not be enough for supporting a windowfarm. feeding habits and fishdensity also plays a role, where i guess that you could theoretically put more fish in a windowfarm aquaponic system as it acts as a good filter and cleans water. go as big as possible would be my approach, suiting your possibilities…

hey Martin. I’m in the same boat as Elizabeth. If the smaller tank with smaller fish did not produce enough nutrients for the plants, would it be safe to add nutrients? If so, which nutrients would be okay? perhaps there is some combination of hardy fish and additive nutrients that wouldn’t hurt the fish. If you don’t know, i might just have to experiment on my own once i get it up and running

honestly I am a college student, so unless I can have a single goldfish in a little tank and also add nutrients, when I build my setup, it will most likely just be an ordinary hydroponics system. And I don’t want to go all Dr. Frankenstein and start killing goldfish with no basis. I read a bit about different species to use, though, and building an outdoor system (suburban) with Tilapia is now a dream of mine.