This is a quick tip that may help all of you that use magnetic algae scrapers... the magnet on the outside of these cleaners has a smooth velvety surface that moves freely on the glass.
Problem: with time, the velvety surface slides out of the magnet leaving streaks of adhesive on the glass and making the cleaning task harder.
Solution: put the outside magnet inside a microfiber bag (for storing eye glasses). The magnet will glide easier on the glass! This will make your cleaning easier and extend the life of your algae scraper.
I hope you find this tip useful!