Wash the gravel. Gravel is often dusty; if the gravel is not properly rinsed, the dust can form and can cloud your tank.
Place gravel in the bottom of the fish tank. Here, it will house the good bacteria left over from the fish waste.
Drill holes in the bottom of the grow bed. Holes should be 1/8-inch around and placed every 2 square inches; they will help drain water from the grow bed to the fish tank. Make one large hole, about 1/2- around, in a back corner of the grow bed; this is where the water pump tubing will attach.
Place one end of the water pump in the fish tank.
Set grow bed on top of the fish tank.
Feed the tubing from the water pump through the 1/2-inch hole in the grow bed. Be sure that the tubing extends to three fourths of the grow bed's height and loops around inside of it.
Trim off excess tubing and fold over its end.
Fasten the end of the folded tube. Use electrical tape.
Fill the grow bed. Use your growing medium; stop just before you reach the top of the tube.
Punch holes in the looped tubing in the grow bed. Holes should be small and placed 2 inches apart.
Cover the looped tubing with growing medium.
Fill the fish tank with water. Plug in and test that the water pump flows into the grow bed, webs through the growing medium and returns back to the tank. If necessary, alter the water flow.
Connect the air pump and air stone. Use the air tubing as a connector.
Put the air stone into the tank.
Plug in the air pump. Bubbles of fresh air should fill the tank.
Check your water's pH. The ideal pH is 7.0. A pH higher than 7.2 or lower than 6.8 should be lowered or raised, respectively.
Let the tank sit for 24 hours. This will deplete any chlorine in the water.
Add fish to the tank. Starting out, for every gallon of water, you should have 1/2-inch of fish.
Add plants to the tank. Ideally, wait 4 weeks before doing this.
Maintain your system. Feed your fish frequent, small amounts on a daily basis. A few times a week, add water in your tank to replace what has evaporated.