What Chemicals Can and Cannot Be Used in Liquid Sprayers (Handheld, Backpack, and Battery)

Applies to: Handheld compression, backpack, and battery-powered liquid sprayers sold by The Fountainhead Group across in-house and licensed brands, including Field King, Smith, Indian, Grab & Go, DEWALT, Craftsman, Black+Decker, Scotts, Roundup, and Ortho. This article does not cover the ULV17 Cold Fogger, which has its own chemical guidance.

What causes this: Customers frequently ask whether a specific chemical is safe to use in their sprayer. Standard sprayers ship with seals and gaskets rated for water-based lawn-and-garden chemistry. Putting an incompatible chemical in the tank can swell or corrode the seals, damage the pump, void the warranty, and create a safety hazard. The right answer depends on the chemical type, not the brand on the tank.

How to fix it: Match the chemical to the sprayer before you fill the tank.

Generally safe in a standard sprayer (water-based and water-soluble):

• Glyphosate herbicides such as Roundup
• Common weed and brush killers, including 2,4-D based products
• Water-soluble fertilizers and weed-and-feed solutions
• Water-based insecticides and fungicides
• General-purpose water-based cleaners

Use these only when diluted with water according to the chemical manufacturer's label.

Requires an acid-rated or specialty sprayer:

• Bleach and sodium hypochlorite solutions
• Pool and spa chemicals
• Acids and acid-based cleaners
• Vinegar, including horticultural or "weed-killing" vinegar. Vinegar is acetic acid and it attacks the seals and gaskets in a standard sprayer. Not right away, but it will.

Do not put these in a standard sprayer. They corrode standard seals and pumps. Use only a sprayer specifically rated for them, such as the Smith Performance acid-resistant line built with Viton seals. Check the model's manual to confirm it is rated for the chemical before use.

Do NOT use in any FGI liquid sprayer:

• Oil-based products of any kind
• Diesel fuel, gasoline, kerosene, solvents, paint thinners, and other flammable or combustible liquids
• Hot or heated liquids
• Any product the chemical manufacturer does not list as compatible with poly or handheld sprayers

Always do this:

• Read the chemical's label and Safety Data Sheet (SDS) first and confirm it is approved for handheld or poly sprayers.
• Follow the manufacturer's dilution rate. Stronger is not better and can damage the sprayer.
• Rinse the tank, pump, hose, and nozzle with clean water after every use.
• Never mix chemicals in the tank. Mixing bleach with acids or ammonia releases toxic gas.

If you are not sure whether your chemical is compatible, contact FGI customer service at info@thefgi.com or (800) 311-9903 before filling the tank.