Hi Rox;

I just move your thread where you can post -- sorry, but I upgraded your user status, without moving the post.

Regarding the brown stuff, it could be algae, or it could be iron from your fill water. Do this:

#1 - Tell us what your chlorine levels are -- day to day -- using your OTO / phenol red test kit.
#2 - Test your stabilizer level, or get it tested and tell us what it is.
#3 - Assuming that your pool was filled with the same water that goes into the toilet, check the inside of your toilet tank. If it's dark brown, you have iron. If it's not, I need to know if you have a water softener on your water line.