Richard bray

Plumbing & Filtration
The plumbing for a media-filled aquaponic system is simpler than other systems, and this makes it easier to maintain. The main plumbing and filtration components required are:

• Siphons to drain the grow beds & fish tank
• Pumps to circulate water
• Aerators to introduce oxygen
• Filters to trap solid waste

The growing medium acts as a bio-filter, which is where bacteria clean the water and transform waste into plant-soluble nutrients.
In a basic setup, water is drained from the fish tank via a U siphon, and passed through a swirl filter to allow solids to settle. Water then flows
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through and floods the grow beds for 15 minutes, while the bacteria in the grow media clean and filter the water and provide nutrients for the plants.
A bell siphon in the grow bed will drain the water, which may then pass through another solids filter on its way to the sump tank. The sump tank contains a pump that replenishes the water in the fish tank, where the water is aerated and picks up more waste material for the next cycle.
Siphons can either be set on a timer, or built to flood and drain manually. Timers can provide some consistency, but require a backup power source to prevent crop loss in the event of a power outage. Manual siphons are more complex to assemble, but require less energy input and are more reliable.
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Worms
Perhaps the biggest benefit of a media-filled bed system is the ability to add redworms. One of the most common maintenance issues with this system is the buildup of solids in the growing medium. Redworms feed on dead plant material and fish waste, then excrete castings that are highly-nutritious for vegetables. This helps keep the bottom sludge layer from causing clogs, and also prevents dead zones of deoxygenated water.
Worms must be clean before they are added into an aquaponic system. Manure worms or worms from a compost pile may carry pathogens that are harmful to humans, like E. coli. Purchase worms from a reputable supplier who ships them in peat moss. When you receive them, separate the worms from the moss and rinse them well.
Worms can survive in either flood-and-drain or continuous flow systems as long as the water is well aerated. They absorb oxygen from the water through their skin, and they can climb up through the media to the surface if needed.
Media-filled beds offer the widest crop selection and the simplest design. They work well for beginners who want a smaller system with a forgiving margin of error. However, they are difficult to maintain on a large scale, and the setup cost is higher than a deep-channel system.
If you’ve mastered the media bed, or you want to focus on higher yield with fewer crops, it's time to move into a deep-channel system.
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