If your tank has been properly cycled, changing of the filter should not cause it to become uncycled or induce a mini-cycle. Contrary to popular belief, filters don't hold as much bacteria as you imagine. If you regularly change filters out, your main source of bacteria will be on the hard surfaces such as gravel glass and decor, where it belongs.dont even do it if the tank is cycled bc then it will be uncycled or you'll atleast have a huge mini cycle
In case where a tank is not finished cycling there is no point to removing the filter. "White floaties" can be a build up of slime coat that can form on gravel, glass, inside filter pick-ups that got disturbed, fluff from the filter cartridge, etc. I wouldn't stress over it until tank has finished cycling. In the meantime you can net it out and verify what it is.