At the end of last swimming season, our local pool company closed our 2 year old Fiberglass pool. A few weeks later, I opened the auto cover and used the leaf rake to remove a few leaves and take a look. After, our net was super sticky and dried stuck together. When they closed the pool, I took a picture of the bottles of chemical they put in, it was Beautec and Pooltec. When they opened the pool this week, I told them to not put anything in it, yet they did put what looked like Shock and Chlorine Pucks. Their brushes were super dirty with sticky stuff after cleaning/vacumming. I got a new brush (the King Fin) which is really cool. I brushed it today and I got brown sticky stuff on the tips of the brush. Luckily, hot water and Baking Soda cleaned the brush. All last season we used liquid chlorine, occasional Muriatic Acid, and occasional Metal Out. At the very end of last swimming season when I opened the pool cover I would notice what looked like oil (probably sunscreen) floating on the top, but quickly dissipated. Any ideas what this brown sticky stuff is?