CHOPS stand for Constant Height One Pump System, is Murray Hallam's System from Practical Aquaponics. This system reduce the number of pump required as in their earlier setup, and I can say its quite an ingenious system.

Apart from the reduce number of pump to one, this system will make the fish more comfortable due to more water in the system and the level do not change much during operation.

Below a simple diagram on the basic of CHOPS, in Murray's site there is a better illustration on the system.

Note :
  • To avoid confusion on CHOPS installation, please refer to Murray Hallam's DVD or his other instruction on how-to construct this system. The illustration I made here is for brief explanation on basic CHOPS concept.
  • Please check CHOP 2 it is an improvement of this : Here
On the above diagram I do not include the fingerling tank on the return line, this is optional in my opinion and it do not change the way this system work.

This system, water in the fish tank is maintained at a constant height above delivery pipe outlet, water flowing out will be distributed to growbeds and subsequently controlled by siphons. Its doesn't matter what type of siphon used here, if its work for you then its good.

Growbed outlet water collected by a sump tank and returned to Fish tank by a pump, according to information from Murray Hallam's site the pump is running 24/7. However I don't see the reason why it cannot be shut off at night. 

One aspect of this system I find beneficial is the pump located after growbed, this reduce pump maintenance significantly due to "filtered water" in the sump.

As mentioned earlier this is an ingenious system, but with any Aquaponics system there are pros and cons. I do not practice this due to one simple fact that my backyard is too small for such a setup, so I am not able to elaborate on this design.

I do wish this system can be shut off at night, partly because noise, energy saving, reduce pump maintenance and also it will give some species of plants a time to grow and stabilized during that period.

To switch off the pump at night, it may need a bigger sump tank to hold all the water above the fish tank outlet. How big is the sump tank will depend on the size of the fish tank.

A word of caution on any sump tank system in equatorial & tropical regions you must ensure mosquito cannot breed in the tank, by either covering it with nettings or have few larvae eating fish reside in the sump.

With this system, it give Aquaponics enthusiast more way to setup their system and see which is suitable for their location, budget and space.


  1. I like this. As to control the flow rate, you can introduce a gate valve at the delivery pipe.
    How if you don't use any pump? Just air pump for aeration. I've sketched a concept here ..

  2. @acanov, where do you get the sketch. Basically with that arrangement, I don't think it will work.

  3. It's my sketch. Just an idea though.

  4. @acanov:
    I really like the idea on your sketch. The draining of the grow-beds without using a pump is really interesting. But I am sure that it wont work this way, because the syphon cannot work when the outer water level (fish-tank) is the same high as the inner water level (grow-bed). Think that would be against all rules I have learned in my physics lessons :)

  5. Dear Affnan,

    Can we use a ram pump for these systems so that we do not use electricity at all and can use it in remote areas of developing countries where there is no electricity. if so can you give us suitable details of a ram pump connected.

    Otherwise you are s source of inspiration and are doing a log towards going green

  6. Charles, I have tried air lift pump. I'm not familiar with what you mean with ram pump. If you could produce enough lifting power any pump is possible. On this system its best to check Murray Hallam's site for better picture of it.

  7. Dear Acanov, this system works its widely promoted by Murray Hallam's based on earlier system that was widely use.

    Its not my idea, I merely sketch this to show samples of Aquaponics system practice worldwide.

  8. Dear Affnan,

    A quick question/comment about the chop diagram above.

    Because the fish tank is draining into the grow bed, not the sump, then durring the fill cycle of the GB, there would be no water flowing into the sump - only water being pumped out.

    Would this not result in the sump being pumped dry while it is waiting for the drain cycle?

    In my chop systems I drain both the GB and the FT into the sump. This way, there is always water entering the sump.



  9. Hi Floyd, It may come to that situation if the pump is strong enough. This diagram is just an illustration I did to explain brief concept of CHOPS for exactly how its done its best to check out Murray's site as link provided on this page.

  10. A few minor suggestions for the tote chops system:
    Find a big, cheap, plastic tub for the sump, so you can use all four ends of the two totes for grow beds, emptying into the tub-sump.
    By burying the tub, you could do away with the cement blocks and planks.
    With a big screen on the intake of the pump, you could use the sump for fingerlings.

  11. Very informative blog. well explained.
    Sydney Aquarium

  12. This comment has been removed by the author.

  13. Hey Affnan! I really love your work, I have been a fan for over a year. You and Murray Hallum have been my mentors. I have a suggestion for air lifting of water. I have built the common bubble lifter and though it is simple, the lift height and flow rate is quite low. There is another system for you to research, it is called a geyser pump. I built a small test unit to try it out. It is very cool. The basic idea is you use a air pump to fill a cavity that has a column of water above it, once the cavity is sufficiently filled with air, the whole bubble it created lifts the column of water all at once at great velocity. the first time it worked I almost wet my pants. It is quite a powerful pump and makes strange noises, better for outdoors. You have to make precautions because the pvc pipe is light in weight compared to the bouancy of the bubble in the vessel, it has to be anchored well. I discovered this information from septic tank websites. I do not know if it is more efficient to move water this way. It is always good to incorporate ideas from where ever you find them! peace from Rock Island Washington, USA