I started using chemi=pure elite 6 months ago when I was having a BAD Hair algae issue in my 225G. After using it I no longer have the HA...Not saying it was ALL the chemipure....I was doing a lot of work too, but I do believe it helped.....I noticed some HA coming back a couple fo weeks ago, and changed my chemeipure elite....and now it is gone again.....
depending on your tank, will dictate how often to change it....it says you can wait 6 months...IME I should change it in 4...