An aquaponics system is an alternative way to grow freshwater prawns (shrimp) instead of in a pond. These are the same shrimp that are bought in stores. You can build a mini aquaponics system to harvest your own prawns. Follow the simple instructions below for a fun and rewarding project.
Step 1 – Wash the Gravel
Wash the gravel thoroughly and place it at the bottom of the tank.
Step 2 – Drill Holes
Drill 1/8-inch or 3/16-inch holes in the bottom of the grow bed to allow water to drain into the tank. These holes should be about every two square inches apart. Drill another hole about ½-inch in size for the tubing from the water pump to pass through.
Step 3 – Install the Water Pump
Put the water pump in the tank and set the grow bed on top of the tank. Put the tubing from the water pump through the ½-inch hole that you drilled. Leave enough tubing to extend ¾ the height of the grow bed. This will need to be able to loop around the inside of the grow bed. Cut the excess tubing and fold the end cover. Seal the folded piece with electrical tape.
Step 4 – Fill the Grow Bed
Fill the grow bed with growing medium up to just under the top of the tube. Then, puncture tiny holes about every 2 inches in the part of the tubing that will loop in the growing bed.
Step 5 – Cover the Loop
Use an inch or two of the growing medium to cover the loop of tubing. Fill the tank up with water and plug the pump in to make sure the water is going to pump into the grow bed. This water should trickle down through the growing medium and back into the tank continuously. Adjust the water flow depending on the tank size and the type of grow bed and pump that you have.
Step 6 – Connect
Connect the air stone and air pump together with the air tubing. Put the air stone in the tank and plug in the air pump. You should see a steady stream of bubbles rise through the water. This provides the fresh air.
Step 7 – Test the Water
Do a pH water test using the litmus paper strips or a pH meter or test kit. The desired pH is 7.0 for aquaponic systems. If it exceeds 7.2, lower it by using a pH down product. If it is lower than 6.8, use a pH up product to raise it.
Step 8 – Leave the Tank for 24 Hrs
Leave the tank to sit at least 24 hours to let all the chlorine dissipate from the water. Putting prawns in right away is possible, but you will have to use a chlorine remover. The water temperature should be 76 to 88 Fahrenheit.
After 24 hours, stock the tank lightly. Increase your stock after about a month. Prawns are territorial, so you may want to consider small pieces of netting to allow them their space. You can add plants or accessories later, if desired.