Product review (4 stars): Flip filter every refill and use humidifier bacteria mix
Like one of the other reviewers said flip the filter every time and use humidifier bacteria mix when  you clean and fill tanks. especially if you have hard water. It arrived fast looks As advertised but when I ordered again it was white mesh on the outside. They didn't fit quite as well as original. I think its a tiny bit shorter but works good.  If you don't use the humidifier bacteria it won't last long. I use the humidifier bacteria mix and flip the filter every refill and the filter will last a couple weeks running non stop. Before it was less then a week without the humidifier mix