How can I build a DWC cooler tub?

When starting a hydroponic system, the first step is choosing an appropriate cooler. Coolers come in various sizes and materials, each with its advantages and disadvantages. In this guide, we will discuss the process of setting up a hydroponic system using a 48-quart Rubbermaid cooler, although Igloo coolers are also a great choice.

Cooler Selection​

Choose a cooler with a dark exterior, such as dark green, as it will block out more light than lighter colors like yellow or white. The cooler should also have insulation between the plastic layers to help maintain the proper water temperature. To further block out light, you can use black electrical tape, PVC plumbing tape, or duct tape.

It's important to note that with Rubbermaid coolers, you may need to cover the hinge area to prevent light from entering, whereas Igloo coolers don't have this issue.

A 100-quart Rubbermaid cooler is another good option for larger systems, as it can accommodate up to four plants. However, it costs around $40 and may require a permanent stand for stability.

Air Pump Installation​

Air pumps are essential for maintaining proper oxygen levels in your hydroponic system. Rubbermaid coolers usually have a small hole on the backside for air pump installation. You can enlarge this hole by drilling through it and cleaning the edges with a scraper or knife. Igloo coolers may have two holes for air pumps.

Use a high-quality, quiet air pump designed for a 30-gallon tank to minimize noise and vibration. Whisper air pumps are a popular choice, but they can still be loud. To reduce vibrations, place the pump on the floor or on a pallet with a towel on top. Do not cover the air pump, as this can cause issues.

Net Pot Placement and Installation​

Next, determine where to place the 5-inch heavy-duty net pots in your cooler. They should be spaced evenly and not too close to the edges or center to ensure proper plant growth. The net pots should sit flush with the cooler lid and be fully submerged in the nutrient solution.

To create the net pot holes, use a plastic circle template slightly smaller than 5 inches. When cutting the holes with a jigsaw, the blade will create the required 5-inch diameter. Clean up the edges with a razor blade and ensure the net pots fit securely.

It's essential to cover the inside edges of the net pot holes with water-resistant tape to prevent styrofoam from falling into the cooler and water from seeping into the lid. This will help maintain a clean and efficient hydroponic system.

Net Pot Depth​

When the lid is closed, the net pots should be submerged at least 1 to 2 inches in the nutrient solution. After a week of growth, the plant roots should begin to reach the solution, allowing the water level to be lowered slightly. In the beginning, however, it's crucial to have the bottom of the net pots in the nutrient solution to promote root development.

By following these steps and choosing the right cooler, air pump, and net pot placement, you can set up a successful hydroponic system to grow healthy plants in a controlled environment.