75 gallon plans

I built an indoor 75 gallon aquarium ebb and flow aquaponics system for less then $150. Now, I cheated a little bit, as the aquarium and stand where given to me by a friend. I purchased the external canister filter on a clearance sale for $79. I bought all the PVC parts, PVC cutting tool, and the plastic tote for less than $50. The lights and timer where less than $20 (again, I got them on sale). I used a $2 bag of landscaping pebbles for the grow medium.

You can apply this following plans to any size aquarium, but at 75 gallons and larger a few things tend to happen that make this set of plans viable.
The light hood is a heavy wooden cover that has the light fixture inside
External canister filters start becoming popular for these sized systems

The aquaponics system can be added to the aquarium without modifying the aquarium at all. The grow bed simply sits on top of the light hood.

To make this simple 75 gallon aquarium aquaponics system, you will need the following items.

    • 75 gallon aquarium
    • aquarium stand
    • heavy duty aquarium light hood
    • external canister aquarium filter
    • under-bed plastic storage container
    • assorted PVC parts to make the bell siphon
    • plastic pots (optional)
    • grow medium
    • Light fixture
    • light timer
    • fish
    • plant seeds

The first step is to set up the aquarium. Place it where it will look good and there is enough support for the floor. All totaled up, a 75 gallon system can weigh about half a ton with a floor area of only 8 square feet. I originally put mine against a wall in the living/dining room next to the kitchen when I was in an apartment. The floor was not happy about this and sagged a little bit. It is now in the basement, acting as a half wall to separate two rooms.

The grow bed is made using the storage container. Under-bed style containers are suggested as they come in large sizes, in shapes close to that of an aquarium, and they are not too deep. The container is placed on the wooden light hood. If you don’t have a wooden style light hood, you will need to provide a support for the grow bed. Many people use or build a separate shelf. Get the largest storage container that will fit where your going to put it. They are fairly flimsy, so they need to be supported well, so don’t get one that’s much bigger than the aquarium lid if you do go ‘too big’.

You have 2 options for placing the grow bed. You can either prop up the bed to allow room for the plumbing to go into the tank, or you can drill a hole in the lid for the plumbing to go through the lid.

The next step is to build the bell siphon and plumb the drain. You want to make sure that the siphon is big enough to drain faster than the pump can pump water into the grow bed. You can build the bell siphon using these instructions. You want the siphon to work with the grow bed empty, but when we add the grow medium, we will be displacing a lot of water, so the grow bed will fill faster. This should make the siphon start easier.

I like to put my grow medium in plastic pots. When you need to work on your aquarium, cleaning, re-arranging, etc. you need to be able to open the lid. This could prove problematic with a growbed resting on it. Having the plants in pots means you can take them out of the grow bed one at a time. Wait until the siphon has just finished draining the grow bed, then move the filter tube from the growbed down to the aquarium. Move the pots to somewhere where their continued draining won’t pose a problem (I like a 2nd storage tote). Pluck the grow-bed off the aquarium hood. If it won’t sit on the floor without spilling the remaining water over the side, poor the excess into the aquarium.

The last thing to do is to set up the lights. I like hanging them so they are adjustable for height, so you can keep the lights only a few inches above the top of the plants.

Plant some seeds and wait a few days for the magic to happen!