Fertilizers and other chemical solutions have a density different than water.

Adjuvants, which are frequently added to pesticides, can alter the properties of the liquid and affect droplet size:
- Surfactants reducing surface tension, make it easier to produce smaller droplets.
- Oils however, increase viscosity and therefore droplet size.

Charts for spray tips figures are based on spraying clean water, which weighs 8,34 lbs per gallon.
Conversion factors must be used when spraying liquids that are heavier or lighter than water to determine the volume of liquid to be sprayed and select the right nozzle.

Multiply the desired flow rate of liquid in GPM or GPA by the conversion factor and then use the new converted GPM or GPA rate to select the appropriate nozzle.

Example :
Desired flow rate  is 10 GPA of a nitrogen solution: 28%N : 10 GPA (liquid 28%N) x 1.13 = 11.3 GPA (water)
> you must choose a nozzle size that will suppy 11.3 GPA of water at the desired pressure.