If you're getting it on your gear, you're using wayyy too much. That's kind of why it comes in such small tubes. You don't slather it on like you do with No-ad or Coppertone, you put a dab (less than the size of a dime) in your hand, rub your hands together, and that's plenty for your face and arms. Same dab for your legs and feet. If you can see your skin turn white after application, you're using too much.
And, from the Stream2Sea website:
Will your sunscreen stain my clothes?
Mineral sunscreens are naturally whitening and may discolor dark clothing or gear. It will easily wash out with soap and water in most cases, and using an enzyme based stain remover will help. For gear, a little soap and water plus a scrub brush will usually remove any staining or whitening.
Our tinted sunscreens use iron oxides for color, and like most mineral make-ups or other sunscreens, they can discolor clothing or towels. The best way we have found to remove mineral stains is to pre-treat with citric acid or lemon juice and let sit overnight before washing in the hottest water your garment can safely handle, and then air dry.