Anybody use other pad material rather than the rena filstar micro-filtration pads?
I emailed rena and asked how many microns their pads are and they responded:
Our micro-filtration pads are rated based on weight per cubic meter. As they are a non-woven material and the pore size (micron size) will vary slightly from pad to pad. As the micro-filtration pad is used in the aquarium it will begin to be fouled overtime by bacterial slime and debris, eventually clogging. In testing a new micro-filtration pad would stop fine powders such as talcum powder, which has a micron size of 10 microns. Clouds in aquarium water have a micron size even smaller. Cloudy water from a material such as clay has a varying micron size typically from 0.1 to 0.8. Our micron filtration pad does a superior job at removing clouds when compared to other filter materials from many competitors. Overtime the bacterial slime and debris buildup on the micro-filtration pad, capturing smaller and smaller micron sized particles, eventually catching all the materials causing the cloud. When the micro-filtration pad is completely clogged, a new micro-filtration pad is needed.

The white microfiltration pad is 150g per cubic meter.
I wonder how that translates in micron size?

i have used the micro filter pads in my xp2 and the super micro filtration pads on my 55 and after a month i would have to change them, but after i would change them the water would be crystal clear, but i decided to try the sheet of filter media that petsmart has, its blue and white and cut it to size and put two sheets of it in there and it works pretty good so far but i also have it on my 30 gallon tho.

I wonder if I should use 50 or 100 micron pads in my xp2.

It will need to be replaced much more often if it filters that much better.