Dual layer vs polishing pad micron

We are not able to get a true micron rating on our fine layer since it is non-woven. This means the micron rating will vary. This fine pad does a great job of trapping fine particles. If you are happy with the clarity of your aquarium then the FilterFirst pad is all you need.If you want to step up the water clarity and quality then a polishing pad will trap finer debris than our FilterFirst pad. Just a guess but about 50% of our customers use our polishing pad along with a FilterFirst dual density pad.I hope this helps, and let us know if we can assist further.