Fertilome Weed Out Lawn Weed Killer RTS is safe for pets if used correctly per product label. You want to keep children and pets out of the area during application and they can come back once it is completely dry
Fertilome Weed - Out Lawn Weed Killer RTS should not be applied to concrete only lawns. If used as directed, the product should not stain.
If using another brand garden hose end sprayer, we would recommend contacting the manufacturer of that garden hose sprayer directly for assistance with troubleshooting the issues you are having with their sprayer.
If using the Fertilome Weed-Out Lawn Weed Killer RTS, VPG can be reached at 855-270-4776 or email to consumersupport@fertilome.com.