Preparing the table and Grow Bed
In this post I want to cover how to prepare a table and the grow bed for your backyard Aquaponics system. Pictured below is a rough table I built for this purpose. It is just a lumber table that I screwed together. It is made with 2x4's and 3/4 inch ply for the top. The table must be sturdy becaus the weight of the grow media is very high, also you will be filling the grow bed up with water over and over all day. It has to stand up to a lot of weight and constantly changing weights. To work on this portion of the project you will need the following:
Sturdy Table you don't mind drilling holes in.
Rotary Tool (like a Dremel) with a basic set of attachments.
Plastic bin for a grow bed.
Small piece of 3/4" PVC pipe. We will use a section of 3/4" for some of the plumbing. Cut a small piece off for a quick measuring guide.
Small piece of 4" PVC pipe. Same as above. You need about 8 inches total, and can cut a small piece for measuring.
Drill
1" paddle bit
3/4" paddle bit
3/4" PVC slip to threaded adapter
3/4" threaded to 1/2" rubber hose adapter
Prepare the holes:
My grow bed is a Rubbermaid, 31 quart clear bin. I bought it at Lowe's for about 5 bucks. I like the clear containers fro grow beds because you can see the water levels in the bed and keep track of your root growth as your plants take off. You can also see when you start to build up the bacteria and algae that is beneficial to you plants. This system has the PVC piping coming through the table and into the grow bed. My last design drained through the paper slot on an old printer table and fed fish water up and over the lip of the bed. This time I am going to have the feed water come up through the bottom. I think this will be better because the feed pipe will work as a drain when the flow stops. To get this right, I put the bin on the table and figured out where my siphon and feed pipe would be. Keep in mind that I am using 3/4 inch PVC for the feed pipe and the siphon will be surrounded by a 4" PVC sleeve. I cut small pieces of these PVC pipes to work on the placement.
After you find a good placement for the 1" drain pipe and the 3/4 inch fill pipe. Use the Dremel to grind through the bin and put a pretty good divot in the table. You will use these marks to make your holes. I used the 1" paddle bit and drilled a hole through the table using the divot as a guide.
Then I centered the pipe over the hole and traced it. Remember that the 1" paddle bit makes a 1" hole, but the diameter of the outside of the pipe is a bit bigger.
I used the sanding attachment on the Dremel to slowly open the hole to fit the pipe. I wanted a very tight fit to prevent leaking and to support the pipe once I inserted it, so I went very slow and tried to put the pipe in several times. I do the same process for the 3/4" feed pipe using a 3/4" paddle bit and then slowly expanding the hole.
Once you have a tight fit, you can leave the pipe in and move on to the next step which is figuring out how high your stand pipe will have to be.
Now for a quick explanation of what the standpipe is going to do for us. It will keep the water level limited to a certain height. we need to figure out what height that will be. Usually about an inch below the top of the bin. Below is a bad drawing I did of a stand pipe that explains more about how it works.
From here you can see that as the water level goes over the height of the stand pipe, it will drain out of the bottom and keep the water level limited to that height. Now, for the plants in our bed, we want to soak the roots very well with the waste water before we drain so we will add another part to the stand pipe that will allow the water to reach the standpipe height then be drained down to empty again. That part is the bell siphon and we will build it during the next part.
Take an eyeball on the height about 1 inch below the lip. Another good reason to have a clear grow bed. Make a note of the height as we will need it for the next part. I hope this was easy to follow. If you have any questions, please comment below and I will respond as best as possible.
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