CQUniversity Centre for Plant and Water Science staff Kylie Hopkins and Graham Fox have installed an aquaponic system at Glenmore State High School with the help of a year 9 science class.

Aquaponics combines aquaculture (fish farming) and hydroponics (growing plants without soil) in one system to produce fresh fish and vegetables.

Glenmore High students fitting the bell siphons into the drainage pipe

Clean water is pumped from a sump tank into the fish tank, forcing fish waste out into a yabby pond. The water then flows into three hydroponic grow beds which are fitted with bell siphons allowing the beds to ‘flood and drain'. The water drains from the beds back to the sump tank.

Kylie has been working with Glenmore High science teacher Karen Carvell as part of CSIRO's Scientists In Schools program, while the year 9 class has been studying ecosystems and food chains.

"The class learnt about the nitrogen cycle within an aquaponic system - nitrifying bacteria colonise the surfaces in the yabby pond and the gravel in the grow beds to become biofilters - where the ammonia fish waste is converted to nitrites then to nitrates which the plants use as nutrients.

"Students will continue to test the ammonia levels in the water to monitor the development of the biofilters. When the biofilters are well established, seedlings can be planted."

Graham Fox showing students how to connect the pipe work

Kylie says the simple system allows the students to grow silver perch, red claw and various herbs, vegetables and fruits in just five square metres of space.

She says the aquaponic system has been such a hit at Glenmore High that other science teachers already have plans to use it in next year's lessons.

The finished aquaponic system waiting for its plants 
Students fitting the hose that connects the grow beds to the yabby pond