The problem with coffee filters is they clog almost immediately when trying to filter water with lots of suspended material. We tried a coffee filter when we needed water from a puddle, but had to give up with less than half a liter after using two coffee filters.
Boston and Cubby said they used a 1micron biodiesel filter. We found biodiesel filters on Amazon.com. If this link does not work, just search Amazon for 1 micron biodiesel filter. We bought the cone for $6.50. You can also buy yards of the stuff, but we were not sure we would ever need that much. We cut out a roughly 5" semi circle. That means we will be able to cut several filters from the cone. So far, we have used it for sandy water and scummy water in the Grand Canyon. It can be rinsed out an reused. They are heavier, probably 1ounce, but much better than coffee filters. As you can read above, others prefer a bandana or nylon.
So our method for very shallow water with lots of suspended stuff is scoop using a 1quart ziplock bag. Pour from that through the biodiesel filter into the squeeze bag or the wide mouth jar we use for our steripen.
Turtle Walking