How to choose between a Solo piston or diaphragm backpack sprayer

One of the most common questions we get is the difference between a piston pump and a diaphragm pump backpack sprayer. Choosing the sprayer with the correct pump is critical for sprayer longevity and depends on the type of chemical formulation you plan to use inside the sprayer.

What’s the difference between piston pump and diaphragm backpack sprayers?

 Piston pump

• Piston pumps have a cylinder housing with a piston that moves up and down when pumping. 
• Most piston models can reach up to 90psi.
• Higher psi will give a smaller droplet size and can provide further reach.
• Use with low-abrasive, low-viscosity spray liquids, such as herbicides and insecticides.
• Easy to repair.
• Do not use with wettable powders, abrasive, or bleach solutions as this can cause premature wear or failure of the pump.

 Diaphragm pump

• Diaphragm pumps have a flat diaphragm held together with screws inside the housing.
• Diaphragm pumps can reach up to 60 psi.
• Can be used with wettable powders, abrasive or bleach solutions.
• Designed with the ability to pass abrasive particles without damage to the pump assembly.
• More time consuming than a piston model when it comes to repair.

 How to choose

So, which spray is best for you? The most important thing to consider is the formulation. Using wettable powders or bleach solution in a piston pump backpack sprayer will damage the pump and cause premature equipment failure.

The diaphragm pump sprayer will safely take bleach solutions and wettable powders, as well as the same liquid formulations as piston pump sprayers. If you use bleach or wettable powders regularly, you’ll see the biggest benefit from a diaphragm pump backpack sprayer. However, piston pump backpack sprayers have two advantages over diaphragm pumps:

1) The higher psi will produce a finer mist.
2) Easier maintenance.

What liquids do you intend to spray?

Solo piston and diaphragm pump backpack sprayers are equally high quality and have many of the same beneficial features. Choosing between the two comes down to what liquid you intend to put in your sprayer. If these liquids include powders, unfiltered, sedimented water, or bleach solutions, then a Solo diaphragm pump back sprayer is for you. If instead plan to primarily use liquid herbicides or fertilisers, then a Solo sprayer with a piston pump is your best choice.