White polishing pads refers to polyfloss that has been manufactured in to a sheet which you either buy already cut to shape for your filter (they charge you a lot for that final step, lol) or you buy a big sheet and cut it yourself with scissors. It comes in all sorts of different thicknesses.
Having your polyfloss in a sheet makes it a little quicker to put back in the filter after a rinse session. Depending on your bioload and similar factors, poly might make it through a few cleanings before it begins to fall apart and need replacing. The assumption is that you have enough biomedia separate from your floss polisher that replacing it represents an insignificant loss of bacteria (this assumption can break down in very small filters I think.)
Polishing pads are part of the "mechanical filtration" media, meaning they trap particles, hold them and if they are organic, allow them to be further broken down by heterotrophic bacteria, staying within the filter and generating further ammonia for the autotrophic bacteria. Poly catches the finest of particles and so the process gets referred to as "polishing" your water to be more crystal clear.
A few years back we had some discussions about how to identify the correct pillow stuffing floss in Walmart and other big box stores that makes good filter poly. I believe the problem was identifying stuff that had not been treated with fire retardant chemicals, but I'm not sure what the best advice was. I remember the upshot was that if you identified the right stuff you had a really cheap source of polishing material for your filters, although not usually in pad form.
~~waterdrop~~
And when I cleaned the filter I used some of the tank water to clean it is that right ?
