Our first step was to dismantle the grow bed we had in the greenhouse and clear out all of the plants. The plants have found a temporary home in our dining room. I dug out the two broccoli plants that were still happily growing in and potted them. They will eventually end up in the new aquaponics system. The huge tomato had to go. There was no easy way to move the tomato but I'm sure it will be replaced by an equally huge one in the new system.
When we finished clearing out the greenhouse and the cedar grow bed, we had a hole left in the floor. Because we were planning to dig a hole in the back of the greenhouse for the new fish tank, we moved the blocks from the backside of the greenhouse to fill the floor. Then Tom started digging. Fortunately, this project is occurring in January. That means the clay soil is moist and easy to dig in and the temperature in the greenhouse is fairly cool - an easier environment for major digging. A few days of digging and we had a beautiful hole for the new tank.
The next big task was to clean out the tank. This tank is an IBC or Industrial Bulk Container and had children's paste in it. Most of it had been cleaned out but what was left was not an easy task. The tank is about 4'x4'x4' and holds around 275 gallons. Tom started the cleaning and I ended up climbing inside the tank and scraping for hours. In the end, we purchased a non-toxic paint cleaner to soften the paste so it could be cleaned out. Then a good scrubbing and it was ready to go in the hole.
We live in the Pacific Northwest and rain is plentiful. Over the past two years, we have added three rain barrels to our yard. The combination of the rain and the rain barrels helped us to quickly fill up the tank with water.
Our grow beds are made of 55-gallon barrels cut in half lengthwise. These had soy sauce in them which was a bit smelly but very easy to clean out of the barrels. It is important when looking for items for a system to make certain they did not contain anything toxic. Some substances can be neutralized but going with items that contained food is a fairly safe way to go unless you know someone who understands chemistry.
With the barrels cleaned, it was time to start configuring how they would go in the greenhouse. I had already played with several layouts and had some ideas, but actually being in the space and laying the barrels out helped.
When we built the greenhouse, we used plastic buckets to hold water and build a "wall of water". The buckets were painted dark brown and stacked on top of one another on the north wall of the greenhouse. These served as our solar heat sink which helps to moderate temperatures in the greenhouse. During the summer, excess heat is stored in the water and it helps to keep the greenhouse cooler. We found it lowered temperatures around 10 degrees in hot weather.
In the winter, the water helps to keep the greenhouse from freezing. When water freezes, it generates a tremendous amount of heat called latent heat. Last winter, the small heater we had in the greenhouse quit working during a cold snap and the greenhouse only got down to 34 degrees F. This was due to the wall of water. The heater's only purpose was to keep the temps above 40-45 for the plants we had growing in the bed. We did lose some with the extra cold but not everything because it did not freeze.
For this project, we decided to use the buckets of water to hold our grow beds. They will then serve a dual purpose of support and heat sink. Hopefully, the same principles will apply and they will continue to moderate the temperatures along with the water in the aquaponics system.