We have decided to integrate the existing 37 gallon seahorse (zoo) tank into the existing 180g display and sump for purposes of temp control and overall maintenance ease for the zoo staff. We also decided to not use an external overflow box to prevent against system failures. Nate came up with great design ideas that would allow us to use our existing pump to power the system along witha ball valve to adjust the flow since only minimal flow is needed for the seahorse tank. So now the question is, do we drill the existing tank for a Calfo style overflow or purchase a reef ready tank. Drilling runs the risk of breaking pretty thin glass but a calfo overflow (as NRogers points out) may be better for a seahorse tank due to flow issues. I have attempted to look online for commercially manufactured reef ready tanks but I am not finding any. Any thoughts on where to find one or should we attempt to drill the one we have. We seem to be past the hottest days of summer so time is no longer critical.