Product review (5 stars): Use Water & Scale Treatment to Prolong its Life
I used to replace my filters (which are expensive!) more often until I treated it.  I have very hard water (22) and very dry air (it's been hovering around zero for over a month now!) since our furnace is always on.  The filter doesn't get as clogged up as fast with the de-scaling properties of this product made by BestAir.

Also, I use Algae & Odor Treatment as a preventative as well (also by BestAir).