Use a magic marker to trace the outline of the top of the net baskets on the top of the Rubbermaid tub to mark where you will cut the holes for the baskets.
Trace the bottom of the baskets inside the tracings you just made of the tops.
Cut out the inner holes--the ones made from the bottom of the basket--with a utility knife.
Make a series of cuts from the inner hole to the mark that indicates the outer diameter of the mesh pots. Make these between 1/2 to 3/4 in. apart. These will allow the mesh baskets to be inserted through the top and will also hold the pots in place. Remove every other tab to reduce upward pressure on the baskets that could cause them to pop out of the lid.
Establish the inner waterline in the Rubbermaid tub. To do this, insert a basket into the cover and measure its depth. Mark the level of the cover on the inside of the tub. Next, mark the lowest point of the mesh basket on the inside of the tub. Then, mark 1/2 in. above the line indicating the bottom of the basket; this is your waterline for the tub.
Place the air control valves on the outside of the tub. Valve assemblies are designed to hang from the side of an aquarium and should fit well hanging over the outside of your tub. Run lines from the pump to these valves, then run lines from the valves to the aquarium stones.
Cut tabs or holes for the three air lines in the side of the tub.
Place the cover on the tub and make two cuts in the cover to allow it to fit snugly on the tub with the valves in place.
Place the three aquarium stones along the center-line of the tub. Space the stones evenly.
Connect the air tubing between the valves and the stones. Route the tubing through the holes or slots you cut earlier.
Connect the air pump to a one-way aquarium valve. This valve will prevent water from entering into and damaging the pump.
Connect the one-way valve of the air input to the three valves for the aquarium stones.
Insert the net baskets in the six holes.
Fill the tub up to the fill line with a nutrient bath. Mix the nutrient bath according to the manufacturer's instructions.
Plug in your air pump to circulate the nutrient bath.
Fill the baskets with rockwool and plant your young plants in the rockwool.