Does anyone have one of these on there tank? How hard are Refugiums to maintain? More specifically can you just hang it on fill in full of sand rock and algae and sit back and enjoy perfect water, or do you have to constantly maintain the refugium or it can negatively effect your tanks water? What size refugium do you need for a 55 gallon tank? Also if you have pictures of your hang on refugium would be appreciated. Lastly does brand matter in refugiums?