KING VALLEY AQUAPONICS

How aquaponics works

Fish, plants and beneficial bacteria working together in one recirculating growing system.

Aquaponics brings fish production and soilless growing together. Nutrients originating in the fish system are transformed by beneficial bacteria into forms the plants can use.

As plants take up those nutrients, water continues through the system and returns to the fish. The result is a connected growing cycle where fish, plants, bacteria, water and equipment all depend on each other.

There are many ways to build an aquaponics system. At King Valley Aquaponics we have worked with several growing-bed styles, including the different approaches incorporated into our Indy-23-based system.

SEE THE CYCLE ↓ EXPLORE OUR SYSTEMS

Basil and leafy greens growing in an aquaponics raft bed

THE BASIC CYCLE

One system. Three living partners.

Fish are fed and produce waste. Beneficial bacteria convert ammonia through the nitrogen cycle into plant-available nutrients. Plants take up those nutrients and the water is recirculated through the system.

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1. FISH

Fish are fed and provide the nutrient input.

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2. BACTERIA

Beneficial bacteria convert ammonia through nitrification.

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3. PLANTS

Roots take up dissolved nutrients from the water.

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4. WATER

Water continues around the recirculating system.

↳ water returns to the fish and the cycle continues

THE GROWING BEDS WE USED IN OUR INDY-23 SYSTEMS

Different beds gave us different strengths. Our system was based around the Indy-23 approach developed by Murray Hallam. The original Indy-23 is a complete family-scale system; at KVA, the important lesson was seeing how different growing-bed methods behaved side by side and discovering where each worked best for us.

1. Ebb & flow media bed

Diagram showing an ebb and flow aquaponics media bed flooding and draining through a bell siphon

Water periodically floods the media bed and then drains away. This repeated wet-and-drain cycle brings nutrient-rich water to the roots while drawing fresh air back into the root zone.

What we found it brilliant for

Propagation and herbs — basil, mint, parsley, coriander and more
The media supports roots and holds moisture between cycles
Excellent oxygen exchange and bacterial surface area
Easy to lift, divide and move young plants

Why it worked: young roots got moisture without sitting permanently waterlogged, while each drain cycle pulled oxygen back into the bed. For propagation and herbs, that balance proved extremely useful for us.

2. Floating raft / DWC

Diagram showing plants growing through a floating foam raft with roots hanging into aerated aquaponics water

Plants sit in holes in floating foam rafts while their roots hang into continuously aerated, nutrient-rich water. Roots have constant access to water and nutrients without being buried in growing media.

Our North East connection

We reused foam raft material left over from the early days of tobacco production in North East Victoria
A simple, practical bit of recycling
Worked particularly well for leafy greens and quick-turnover crops

Why it worked: lettuce and other leafy crops could put roots straight into the oxygenated water, giving them a simple, consistent growing environment.

3. Constant-water media bed

Diagram showing a constant-water aquaponics bed with solid media, submerged water zone and overflow

This bed keeps a more constant water level through solid growing media. Roots remain in a stable, moist environment while the media provides support and extensive biological surface area.

Where it fitted

Good for larger and longer-term plants
Physical support for bigger root systems
Media contributes to biological filtration
Stable root conditions with constant moisture

Why it worked: the solid media supported heavier plants while creating a large surface area for bacterial activity and a stable root zone.

About the Indy-23: our system experience was influenced by Murray Hallam's Indy-23 design and training with Practical Aquaponics. We acknowledge that history while describing here what we observed and learnt from operating our own system in North East Victoria.

Read about the original Indy-23 design →

FISH & WATER

The other half of the growing system.

Fish swimming in an aquaponics tank — Fish are the nutrient engine of an aquaponics system.

Healthy fish, adequate oxygen, consistent feeding and stable water quality are central to aquaponics. Fish are not simply an add-on — what happens in the fish tank affects the bacteria, nutrient supply and ultimately the plants.

Over the years we sourced fish from a number of suppliers, including interstate. Today we can source native fingerlings much closer to home through Glenwaters Native Fish in the King Valley.

Glenwaters has supplied native fish since 1986 and offers fingerlings for collection or freight. Having a specialist supplier nearby gives us shorter transport distances and access to local advice.

See Glenwaters fingerlings →

What matters

Healthy, active fish
Plenty of dissolved oxygen
Consistent feeding
Stable water temperature
Regular water-quality testing
Reliable aeration and pumps
Good biological filtration

WHY AQUAPONICS?

Efficient use of water and nutrients.

Because water is recirculated rather than continually discarded, aquaponics can be water-efficient. Nutrients originating from fish feed are recovered by the plant crop while the same infrastructure supports both fish and plant production.

It also comes with trade-offs. Aquaponics requires equipment, energy, regular maintenance and knowledge of both plant and fish production. For KVA, the important part has always been understanding what works in a real system rather than presenting aquaponics as set-and-forget technology.

EXPLORE OUR SYSTEMS →