I very rarely clean my filters as long as they flow right, plus as far as I'm concerned that's all beneficial bacteria, plus as someone else said I think slightly dirty filters clean better, not to mention I always find a way to makeshift my filters and add extra carbon or extra filter floss, don't panic bro you will be fine and I would clean out 1 filter at a time not both at the same time you want to stay steady while the other builds up it's bacteria and it's proper dirty levels for optimum filtering.. but than again that's just what I would do....