hi i have couple questions hope dont sound to stupid.. I’m from digby nova scotia canada and want to start little cleaning buisness to clean mos off of roofs.. first question is where can i buy the SH.. can i buy from pool store in city.. and second if i spray on roof and it giving fine for week can i leave it on till it rains or do i rinse it off. if i rinse it off with water how long do i leave it on before i rinse it off and thanks a million