Product review (5 stars): Seem to be comparable ones that came with the humidifier
May be a little thinner, but seems to add humidity at the same rate.  I generally get a winter season out of each, but that does require you to pull the filter out and soak it in bleach and vinegar about every 5 weeks. Yes, they get crusty if you have water with a lot of minerals in it; soaking the filter helps that, too.  I assume people having mold problems are not running these constantly...you must or the water sits and mold grows.  If you keep it running, you may start getting some after a while, but then soak it.

Of course I'm cheap and you may toss the filter when I would soak it.