i clean algae off the front and sides but never the back. then it gets really thick and brown, it starts growing in lines that look like little brown worms. why does it do that? is it a bacteria or something that feeds off the algae?
Algae will eat some things from the water. Stuff your plants will also eat. By eliminating either light, and or nutrients from the water. Im pretty sure there are more things, But I cannot think of them at the moment.
Just scrape the algae from the back. Simple. A bit of elbow grease will do the trick.