I have a C-220 and C-360. I only open them up once a month, mostly to change out the fine particle pad. The rest of the media is bio balls, Chemi pure and such. I disconnect the filter and carry it to the bathroom and pull out all the trays, dump the water, rinse the trays in old tank water and put everything back together, then re-hook and push the prime button to refill the filter. I've never had any trouble doing this . . .