What pump for Aquaponics?

Choosing the right pump for Aquaponics is a question often raised by new people interested in building their own system. For many it will be often their most expensive decision. The pumps main purpose is to lift water to a certain height. If we could harness a waterwheel on a stream to do just that – our job would be done. Failing that and living in an urban environment – we need to choose a mechanical device that is energy efficient, inexpensive reliable that can do that job 24/7 for many years – with minimal maintenance.

Its really about balance. You won’t need a heavily rated pool pump with a lot of grunt to do something that a much smaller pump can do more efficiently.

So what sort of pump should you use for your home?

Chinese made Block4500 pump

A good all round pump for a fish tank of around 1000 litre capacity is this Block4500 submersible pond pump. A lot of European manufacturers now build their pumps in China. This pump is based on a solid German design I am told – but without the badge. Here at Ecofilms we have been running this pump 24/7 for just under two years without any problems.

It is quiet running and easy to maintain. It has a removable grille cover on the front that is easy to clean. Just unsnap the outer grille guard and rinse any muck in a bucket of water and snap it back on. Your weekly maintenance is complete.

This pump is rated 100 Watts but do a check with a power usage meter as in our aquaponics system it runs around 66 Watts under load. Head or water lifting capacity is 2.4 metres which is fine for Aquaponics. Your pump only needs to lift water a few feet to the grow bed. Its job is complete.

The water will return back by gravity. This pump will turn over 4500 litres per hour and water quality in my tank is always crystal clear. You could run a pump of slightly less power in a 1000 litre system but the added grunt means it squirts out into the growbed any biofilm crud buildup or blockage of matter without problem. Choosing a smaller pump rated around 3500 litres per hour can save you a few dollars but has proven to be a little underpowered for a system of this capacity.

A look inside an Aquaponics Fish Tank

Choosing a much larger pump would only be a waste of energy. Our electricity costs per year to run this pump average around $100 for the year. We have about 50 Jade Perch in this tank all growing very well and approaching the 450 gram size with no problems. The Cost of this pump is around $115 and for that amount of money you should buy two and keep one in the garage as a spare. Thats what we do. If the pump should ever die – you want to protect your investment of fish and snap on a new pump in seconds.

A look inside a fish tank can be a bit baffling to many people at first with an array of pipes and pumps and lines – but its fairly simple if you break it all down. In our Maximus tank designed by Murray Hallam you will see the main pump (Block4500) working constantly pumping the water up to the main grow-beds non-stop. Next to it is a smaller 12v marine bilge pump. It is turned off. It only springs into action if power to the system is interrupted. In the event of power failure – a relay switch out side the tank powered by a 12volt car battery switches on. No water is pumped to the grow-beds. They will survive fine. The purpose of the smaller bilge pump is to splash water back onto the fish – supplying them with adequate aeration and the vital oxygen that is dissolved in water to keep the fish alive. Without air – your fish will die. Notice the ball float. It acts as a cistern topping up water in the tank as needed. In the summer months, normal plant transpiration will result in about 10% of your water loss. This is normal and nothing to be worried about.
More knowledge on pumps is provided in the Aquaponics Secrets DVD that we made with Murray Hallam. We’re proud to say it gets rave reviews by the people that actually use Aquaponics systems. Now thats great praise indeed.