Late spring through early fall is known to many parks and rec spray techs as the busy season. This is also the period when spray equipment gets the most use and when an equipment breakdown or failure will have the biggest impact on productivity, scheduling, etc.
At the end of the season, take a proactive approach to ensure the system is ready to go for the next spring. A reasonable place to start is cleaning the water tank since this area typically doesn’t receive much attention.
Tanks often experience a buildup of chemical residue from fertilizers, herbicides and pesticides falling out of suspension and accumulating on the bottom. This can cause a variety of problems. For example, material near the bottom of the tank--once it is combined with the residue--may have a higher concentration than what is supposed to be applied, or a different chemical from an earlier mix may be applied inadvertently.
Lingering residue also can clog filters, hoses, fittings, guns or tips. A clogged filter may starve a pump, causing serious damage, possibly even total failure--all of which will stop you in your tracks and send you back to the shop for service. In the worst-case scenario, debris buildup can be so severe that the tank must be replaced (see photo).
To clean out a tank:
1. Drain the tank as much as possible without running the pump dry.
2. Fill the tank with clean water, and run it through the system. Remove the spray gun so it does not become clogged. Check the filter periodically to ensure it doesn't clog. Be sure to follow all label directions when disposing of the rinsate if it contains chemicals such as an herbicide or pesticide. You may want to spray the rinsate into another tank on a different truck.
3. Add some clean water to the tank. Don’t fill it completely this time, but just add enough to feed the pump and fill the hose. Most of the tank should be visible. Turn up the pressure and use the spray-gun pressure to wash the inside of the tank. Add more water, and then spray out the rinsate as stated above.
4. Fill the tank with water and add tank cleaner (available at any fertilizer or herbicide supplier). Most of these products use one pound of tank cleaner per 100 gallons of tank volume. Put the spray-hose end into the tank, and let the system circulate the tank cleaner for a while, following the label directions. This will remove any remaining chemical residue. Properly dispose of the tank-cleaner rinsate.
5. Run another tank of clean water through the system to remove any remaining tank cleaner.
6. Sometimes there is debris remaining in the tank after the cleanout--stones, bottle caps, etc. I don't have a real solution--but this debris will have to be removed manually so it doesn't cause problems later. If the filter is at a low point in the system, it might be easier to remove the filter and use a garden hose to wash small debris, such as pebbles, out of the tank and through the filter.
7. Finally, check and clean the filter to ensure it is debris-free.
A clean tank requires some regular effort, but it’s worth the reduced downtime, better productivity and decreased equipment repairs.
Andrew Greess is the President of Quality Equipment & Spray, which designs and builds custom landscape, golf- and pest-control spray equipment solutions. He can be reached at firstname.lastname@example.org