thanks for the reply, I guess i should feel them, i just looked at them, they are still the blue like when i first brought them.The bioballs will get discolored and feel a little slimy, that is the bacteria. No, they don't need light to grow.
OH! i just felt them...they are not discolored, and they are not slimy. They have been are operation for about two months now. I do have a blanket media cover on top of them. They are in a blue plastic 30/40 gal drum, water is sprayed over the top and repumped back into the sump at the bottom of the drum.