Zero-tol. It is a concentrated (compared to drug store kind) hydrogen peroxide stabilized with peroxyacetic acid, so smells like vinegar.
I carry quart, ready-to-spray bottles that attach to your hose end for application. I recently sprayed my entire greenhouse to eliminate algae (Boy, did it ever!), and it didn't harm a single plant, bud, or blossom.
They also make a ready-to-use spray bottle, but I'm having a hard time getting them.