well i went to change my filter because they are filled with diamond activated carbon, and if i dont change em, they release nitrates n stuff back into the water, so when i pulled 1 of the 2 out, wich the one i pulled out is the oldest, i noticed some maggot looking type worms, 
but they wer just chilling in the netting and they had little fangs, and a bunch more critters were attatched that only like the dark, so my question is, the filter needs to be replaced, and im scared to just throw out these little things, are they helping with anything, and will they come back, im in an odd spot.... i need some opinions pleeeaaase... 
but they wer just chilling in the netting and they had little fangs, and a bunch more critters were attatched that only like the dark, so my question is, the filter needs to be replaced, and im scared to just throw out these little things, are they helping with anything, and will they come back, im in an odd spot.... i need some opinions pleeeaaase... 
