A second pump built into your CHOP Mark 2 operating system to provide redundancy. It may seem to be a contradiction to add a second pump to a CHOP system but it is not such a bad idea. Pumps are a mechanical devices and therefore are subject to failure. Even the most expensive pump will give out one day. Obviously we will fit the best pump we can afford to our CHOP system, and being prepared with an additional pump at the ready is a good idea.
It is very upsetting if you have a pump failure and there is no readily available replacement. With no water movement and exchange the fish tank will quickly become polluted and fish deaths will soon follow. Pumps have a uncanny ability to fail in the middle of the night, at weekends or when you are away.
Fit a second pump to provide water security for your CHOP Mark 2 system.
At the very least, have a replacement pump on the shelf at home complete with fittings to allow you to make a rapid change if it becomes necessary. Have the joining system already attached so that rapid changes can be made
Left:- Snap on fitting. Right:- Barrel Union. Examples of ways to quick connect and disconnect your spare pump.
Another way is to have the second pump actually plumbed into the system ready to go at the flick of the switch. I run two pumps on each of my two bigger systems I have running. The Quad kit and the Homestead kit. I am gradually moving through all my other systems and fitting a second pump to each.
Each pump is fitted with it’s own independent pipe system leading from the sump to the fish tank or grow beds, in waiting ready to work in an instant. If pump “A” fails or needs maintence down time, pump “B” is brought on-line. Have both pumps sized (capacity) so that each pump is able to run the system by itself. A little over capacity is not a bad thing in this case. Additional expense in pipe work is the downside to this plan and if the operating pump fails for any reason, there is no automatic switch over to pump”B”.
Run both pumps in parallel. This is my preferred option. It is easy to set up and is worry free. Have both pumps sized so that one by itself will just run the system but has no over capacity. Having the pumps sized down a little will save on energy costs while giving the system safety you desire. A bit like a single engine or twin engine aircraft.
Here is how to connect the plumbing so that both pumps can be hooked up ready to go. I am showing two alternative pipe layouts for your consideration.
See as per the drawing. Each pumps is run via a pipe through a “Non Return Valve” then the two pumps output pipes meet at a “T” joiner to bring both pump outputs into the one line where the water is then run to the grow beds and fish tank.
If one pump fails the other pump will carry the load. The water will be prevented from flowing back through the failed pump by the non return valve.
Alternatively, one pump can be run directly to the fish tank and one to the Grow Beds with a balancing pipe between.
Pump and Pipe Layout "B". This layout will deliver more water to the fish tank and grow beds than layout "A" This is because we are using two pipes instead of one to deliver the water. If one pump fails the water from the operating pump travels by the balancing pipe to the other line and is prevented from back flowing into the sump by the non return valve.
It is important to have both pumps of the same capacity model and brand. If one pump has more capacity than the other it will do all the work and the other will be “lazy” It is also important to have correct sized pipe to carry the volume of water easily. Too small pipe diameter will cause reduced flow and loss of pump performance.
This arrangement works well with any style of system layout. If you are not running CHOP or CHOP Mark 2 this pump arrangement will work well for you eliminating one possible failure point in your Aquaponics system.
Murray Hallam at Practical Aquaponics.