The older rolls used to have it printed on them, I'm guessing that's where the number came from. Not sure if that has changed, I use the Precon 20 now. I'm going with the same plan you outlined.Are you sure red sea is 200? That would be amazing if so. I have not been able to find any good information verifying that. I don't plan to take mine off for a little while in the beginning either. I found this thread but it doesnt really give a substantial answer. https://www.reef2reef.com/threads/is-the-reef-mat-roll-really-200-microns-i-don’t-think-so-pictures-provided.1128914/
I will just leave it running to change as little as possible for now and in another month or so turn it off for a week and let the water overflow to see how my tank/nutrients are affected.

