cleaning "mature" screen?

[new2scrub]

santa do you have a good picture of just How clean you should strive to get a mature screen one that has been running for a year or more? Now that my screen is mature it is sometimes hart to tell if I am removing to much or not enough algae.

[SantaMonica]

Start using a hack saw blade:
http://www.youtube.com/watch?v=d9fMdJRmYGM

[new2scrub]

ok looks like I am getting it about as clean as you are there,but I will def try the hack saw blade next time because it took you one tenth the time to do it! THANKS