I just changed mine at the year mark with a Maxetw-975. No tools required.
Make sure that both rubber gaskets are on both ends also. As one dropped to the ground but I caught it when I inspected the filter before I installed it.
Less then a 10 minute job.
I think the brown color of it came from a campground outside New Orleans. They were on well water. The owner even said that if you filled a bucket, you would see a brown film on top of it. But he tests the water regularly. Here is a pic side by side. Can you tell which one is new? LOL