Aquaponics: CHOP2 Revealed

You gotta hand it to Murray Hallam. He’s always tinkering with his aquaponics systems and trying out different approaches on how to improve the plumbing. While we were filming him over a year ago for the “Aquaponics” The First 12 Months” DVD we caught Murray on camera just watching intently how the return pipe was dumping water back into his fish tank.

“I just love watching the way it all works.” he said “I take simple pleasures like that. I really do.”

So its no surprise that Murray would try to innovate the CHOP based system that countless users around the world have adopted with great success. Murray explains that in the old CHOP method water is pumped up from the sump to the fish tank and from the fish tank runs back to the grow bed and sump by gravity. This system works very well but it requires that the grow beds be perfectly level to function properly. With CHOP2 there are a number of advantages you can study if you watch and play the accompanying animation.

“With CHOP2 you will notice that the pump sends the water to the grow bed as well as the main fish tank.” said Murray, “The water from the fish tank and grow beds runs back to the central sump.”
“It’s kind of like a double loop water flow with the sump as the central mixing point. It works extremely well.”

So what are the advantages of modifying your system to CHOP2?

Murray Hallam

The main point as Murray explains is that grow beds do not need to be perfectly level to function properly. A crucial point if you are running a number of them on uneven ground and have encountered problems with your auto siphons. Because each grow bed has an independent ball valve, the water flow can be regulated with greater control than gravity fed flow under the old CHOP system.

More Control

Because each Fish Tank also now has its own ball valve it means water flow can now also be regulated as well.

“If you need to harvest your fish and control the water depth or do any maintenance at all,” said Murray, “You now have complete control to stop water flowing to your main fish tank or even drain it, but not stop the flow to your other grow beds.”

More control for the aquaponics enthusiast also means more control over winter temperatures as the mercury plummets.

“For the first time now, users can turn off their grow beds at night but still have their main fish tank running as normal.” Said Murray. This is a great boost for owners who complained that their grow beds were acting as a heat sink at night, plunging their water temperature down a number of degrees.

Modular Design

A side benefit for users who will modify their system to CHOP2 is that should they decide to change their system from a gravel based media to floating raft, CHOP2 will accommodate their design shift.

“If a combination media and raft system were to be built,” says Murray, “Swirl filters or regular filters can be fitted easily into the fish tank to raft section, then we can allow the rafts to drain back to the sump.”


As Murray Hallam points out, “The critics will say that the sump pumps half the water back to the fish tank. Surely this can’t be good for the fish as solids are returned back to the main tank?”

Logically this may seem to be the case, but over a year of trialing this system with hundreds of fish Murray has discovered that the sump itself acts as a settling tank for solids, something he didn’t expect to see and something that never happened under the old CHOP system.

“You will need to clean your sump out occasionally as the solids will be noticeable around the sides of the sump.”

Solids removal from the fish tank is always discussed on Aquaponics forums so does CHOP2 stand the test of time?

“We were worried about that in the first instance as well. It is one reason why we have been sitting on the idea for so long wanting to make sure there has been a really long test of the idea. It works a treat, the fish grow healthy and happy, the plants the same and all the while the plumbing is easier to set up and run.” said Murray.


What about fish nutrients? Aren’t you halving the number of fish nutrients by returning the flow back to the main fish tank?

“Some may think that the nutrients from the fish tank will be diluted as the sump water is pumped partly back to the fish tank and partly to the grow beds,” he said “but in just over 12 months of running we see no reduction in nutrient to the grow beds.”

Murray sees CHOP2 as a definite improvement for the Aquaponics community around the world.

“Come back in 12 months time as see how many users have modified their system to CHOP2.” He grins. “People always vote with their feet. They know when they’re onto a good thing.”

Community Reactions

Within minutes of launching his new design feature to the Aquaponics community around the world, began to buzz about CHOP2. Veteran Aquaponics users gave it a cautionary thumbs up as they began planning changes to their systems. Younger users were more excited. One forum member exclaimed, “Outstanding and yet so simple. The chop2 system has solved the very problem that has been delaying my progress with getting my system started.”

How do you build it?

“Aquaponics: The First 12 Months” DVD will feature an exclusive demonstration by Murray how you can adopt his design features into your own aquaponics system.

You don’t need to buy his kits to enable this feature to work for you. Murray has built a number of test systems using IBC tanks.These tanks are commonly found around the world. If you can source a number of these tanks in your country and grab a hold of Murray’s “Aquaponics: The First 12 Months” DVD which will be out on his website very soon – you will be shown how to do it the right way as we delve further into the exciting world of CHOP2.