So back to the aquaponics…
With a consistent scale, the new and accurate plans for the system look like this:
As you can see, the unit fits into the corner with two grow beds running along either wall, and the water tanks creating the triangular shape underneath. The tank is divided into two sections for two main reasons. First, it provides a biofilter section in the back which will be filled with inexpensive door screening to provide lots of surface area for bacteria to grow. Second, by drawing the water from the back and in filling from the front, that will leave the front portion with the fish at a constant level, even when the grow beds drain into it. In order to get good circulation of water, the drain pipe from the front to back will start at the bottom of the tank, go straight up and then empty at the top of the water level through the divider. Makes a lot more sense when it’s done, I promise.
The frame-work of the tank uses stacked 2x4s for the sides and 4x4s for the vertical posts. I was concerned about the amount of pressure this volume of water would create, so I had to make sure the corner joints would hold. By placing the vertical posts on the outside (mounting the 2x4s with three 4″ screws apiece), the force of the pressure is put against the post as opposed to pulling away from it if the posts were on the inside.
And remember, this has to be aesthetic too! To give it a nice simple look, I opted for a red stain and sealer for the vertical posts and top boards, and a blond sealer for the 2x4s. Also, because this was going directly on the rubber floor, I didn’t need to cut a base for the tank portion since the rubber floor is well insulated and doesn’t have any sharp edges. Once the frame was constructed, I put in pond liner in the two tank portions and secured them to the upper edge with screws and 2x12s that I used for the upper edging. I made sure that the inside of the frame was free from splinters and jutting screws so that the liner wasn’t punctured. The drains from the front to back were two drains of 2″ PVC that were sealed at the edges around the pond liner with a special expanding sealant used for water features.
Once all was said and done, we filled it with water and started the pump. We’re using a 300 GPH pump to be sure we get adequate flow to the two grow beds and center waterfall system. I put some river pebbles in the bottom of the front pool so that the eventual fish won’t be able to swim up the PVC. And in the back around the pump, there is 25′ of screen. Roughly, the front and back tanks combined are around 400 gallons. As they say, “Ta da!”
I’m going to let the water circulate for a while before adding any fish and aquatic plants. I really should have rinsed the stones before putting them in, but I didn’t realize just how much particulate grit was in the bags. Nonetheless, the sound of the flowing water adds a nice ambiance to the space, and can’t wait for my next free afternoon to sit out there and read!
It’ll be at least another week or more before I can have the grow beds put together (though the lumber is already cut). And I still need to purchase the expanded clay pellets that will serve as growing medium for the plants. When working on a budget, some things just take time. Thank God for monastic patience!
Tune in next time for “Back out in the wild: What has Br. Addison been up to out there?”