you can get sheets of low micron poly pad. i don't think this would work well in an emp though. the pressure needed to drive the water throught the filter would more likely send it up and over the filters bypassing them alltogether.
if you have a powerhead go to your local menards/homedepot or walmart and get a cheap pleated 20 micron whole house water filter cartridge. put this over the intake on the power head and watch the tank clear.
oh yeah i forgot to tell you that you need to plug the hole on the other end of the cartridge to have this work a soda cap or threaded male 3/4" pvc plug should do the trick.
most of the cheap ones say they are pleated paper but some are actually pleated polyfiber (i find these at menards most of the time labeled the same as the paper ones). the polyfiber ones are shiny white not dull white and last a little longer than the paper ones. with the omni filter brand the polyfiber ones are slightly larger in diameter.
if you don't mind possibly wasting the money you could try them but i don't think they would work very well. if you decide to try them let us know how it works out.