How can I build a DWC cooler tub?

The first step is, selecting a cooler, and each has its own good and negative qualities. For this faq, I will be using a 48qt Rubbermaid, though I prefer the igloo coolers the best. The dark green exterior of the cooler will help block light more than a yellow, or even a white.

They all should have insulation between the plastic, to help maintain the right water temperature. Also, if you want, you can use black electrical tape, pvc plumbing tape, or duct tape, to help keep light out.

I should point out with the Rubbermaid, you will have to add paper, or duct tape, to cover up the hinge on the Rubbermaid. Light can get in there. Igloo coolers don?t have this problem.

Other good coolers to use: the 48qtr cooler by Coleman/igloo. They have wheels, easy pull handle, (which makes it easy pulling it out, when it comes to changing the nutes). But, they have poor colors, the internal insulation is thinner, and the bottom is not flat due to the roller wheels, which makes it difficult to use a long or even a short air stone.

The 100qt cooler from Rubbermaid is another great option (I suggest making a permanent stand for this one, cause it would be a bear to move) This cooler has two lids, a main one for the plants, and a smaller one off to the left side – perfect for checking roots and filling. Also comes in dark green, 4 plants will fit, but costs $40.

The airpump

The Rubbermaid has a small hole on the backside. First find the hole under the lid, and use a small drill bit and drill upwards thru it. Find the hole on top, and drill back down with a bigger drill bit. Then just use a scraper or knife to scrape off the edges. Enlarge this hole by drilling.

The igloo should have two of them, whereas the Rubbermaid has only one. I plan on using only one air pump, rated for a 30gallon tank. Cheap air pumps are louder, and that can be really annoying, especially for a stealth grow. I?m using a Whisper, but they are still loud IMO. I find placing air pumps on the floor will create a vibration thru the floor. If you have to use a pallet, then use one, and place a towel on top of the wood, to help ease the vibration down some. Don?t cover up the air pump though, or this could lead to problems.

Don?t put the air stone in until after all the drilling and the mess has been cleaned up.

Construction:

Net pots

Now onto figuring out where to place the 5? heavy duty net pots. You don?t want them too close to the end, or too close too the center, and they need to fit flat down onto the lid. You want the net pots all the way down in this cooler, so they will dip into the nutrients. The cooler lid is around 2.5? thick, and if you ever have to move it in the beginning, you don?t have to worry about water pouring out the sides.

For this cooler, I decided to make the center of the net pots at (for both), 5 ¼? from the center, and that would also be 3 ¼? from the outer ends, and 5? down from the back of the lid. This will allow the net pots to lay flat.

Netpot holes

Now before making the holes for the net pots, I went ahead and cut out a plastic circle. It is just under 5?, and will be used for a guide line. Reason for not being exactly 5?, is because when I use the jig-saw, the blade will make it the 5? that I need. I put tape on the plastic circles, so they won?t shift when cutting them. I then trim it up with a razor blade.

Check again to make sure the net pots will fit securely, and fit close to top surface of the lid.Remember to clean it out before continuing on.

Also use some duct tape (preferably water resistant tape) to cover the inside of the edges where you cut the 5? circle out for the net pots. Styro-foam (inside the insulated cooler lid will be exposed) will fall into the cooler, and water may work itself inside the lid, which can turn into a not so clean cooler. I use a thick sticky black electrical tape to line the holes, so installation won?t fall out, and then lined it with water resistant duct tape.

Netpot depth

I want to make sure, when the lid is closed, the net pots will go at least 1″ or 2″ into the nutrient mix. After a week of growing, the roots should be starting to drop down into the mix, and then you can let the water drift a few inches under the net pots, but in the beginning, I want the bottom part of the net pots in the medium.