Just like the title says, should I be cleaning my hang-on refugium? If so how would i go about it? The water doesn't move through it very fast, so the top gets pretty stagnant, theres really no movement on top, but a nice flow through the middle. I stir it once a day, using my finger and whirl it around. Does anyone have any suggestions on what to do with that and also the cleaning situation. Should I add snails in it? Or hermits? Thanks for any help.