NFT # of Plants to Tank Size Ratio

[Brandon Becker]

Hello,

I'm new to the Forum, and very excited to be involved with Aquaponics.

I'm building a NFT Aquaponics system.  I'm using a 35 Gallon tank and the channels will be 3"X2" Rain Gutters.  Can anyone help me out with proper # of plants that a 35 Gallon tank can sustain.  I know it probably depends on the # and size of fish, but are there any rules of thumb to go by.

Some additional information, I will be using Koi or Gold Fish,  I will be planting primarily Basil and leafy Greens.

One last follow up question.  When building an NFT system of this size, is it necessary for an additional bio-filter?  Could I just use a Marine Land Bio Wheel filter in the fish tank?  Do you also need to be careful that a BIO wheel filter such as this one could eliminate the good bacteria or the elements the good bacteria need(when your washing out the filter)?

Thank You,

Brandon

[Averan]

For a tank that small I'd stick with goldfish.  I've got a 55 gallon tank with 8 koi (they get too big to stock more densely) and a 30 gallon gravel bed for bio-filtration and it isn't producing enough nutrients at this time of year to power the 25ft of NFT pipes.  I have 35 plants/holes in the NFT.

You can't skip the bio-filter.  That is possibly the most important component in an aquaponic system!  Sure some folks don't care and will assemble a simple system without one, but if you really want to grow food and have a stable system you need to design in space for the bacteria to grow as well as for the solid fish poo to collect or break down.

Hint: you don't want all those solids building up in your NFT!

Hint2: don't use a silly aquarium filter or any filter that you have to constantly 'wash out'!

[Cory Cramer]

I have a 29g system that I grow leafy greens in and I grow 12 plants at a time right now with no problems. So, you can at least grow that. (This is a goldfish tank.) I don't see any reason why you couldn't use a standard aquarium filter for your bio filtration and solids filtration. I started my system with one and then built my own later after the system was up and running.

[TCLynx]

The filtration is the most important part of aquaponics.  A system can get by sans fish or sans plants for a short time but if the Filtration is not present and you have either of the other two then things tend to get ugly or smelly fast.

Now you could use an aquarium filter provided it is appropriate to the amount of fish you will have, drawback with aquarium filters is all the extra work you have to put into them which is why you might be better off having a grow bed that can do the job while also providing you more plant space and reducing the amount of effort you have to put into the system.

Number of plants related to fish tank, well that is all going to be heavily related to the amount and quality of feed you are giving the fish and the type of plants you grow.  If you have good filtration, you can likely add more plants (more NFT) if you find you are not removing enough nitrates regularly or if you install lots of NFT spaces and find you don't have enough nutrients to go around, you can always just plant less plants or add more fish if you have enough filtration and tank space to support them.

Truth is it will all be a balance and how your system will balance out will have too many variables for some one else to predict based on fish tank size alone.  And NFT systems are not as common so the rules of thumb for how to design and size them are not as well figured out as it is for media bed systems