[I have a 90 gallon DAS reef tank and I would like to add a refugium to it. I am looking for some ideas on how to implement it. For those of you who have not seen a DAS there is a 3" ledge of glass going around the top inside edge of the aquarium making it difficult if not impossible to hang a hang on overflow. I currently have a 29 glass aquarium I would like to use for the refugium if at all possible. I am trying to make this a system that would sit beside my DAS as a kind of a show refugium. If anyone has any ideas please let me know. Thanks all.]