Roller mats work great. Sometimes even a little too great. What I mean by that is that a roller mat with the NP BACTO Balance is fine, just keep an eye on your nutrient levels. In some cases the roller mats are SO efficient in removing particulates, that they do a better job than is needed in relation to nutrient content. In those cases the system becomes almost "too clean" and, no matter how hard your try, you can't seem to get the nutrient levels up to where you would like them. Don't get me wrong, I am not against rollers. In fact, I think they are great. This is just something I have seen more than a hand full of times, and it's worth mentioning as a situation to be aware of a watching for.