Hello guys I have a 40 tall tank and stand I'm gonna replace the broken top rim on and reseal. I wana make a marine tank out of it but want to build on end of the tank into a in tank sump. Kinda like my old aqua pod had. I plan to build the wall to seperate it and cut the drain fins. My question is on how tall should I make the dividing walls between the the three chambers? And should they extend all the way to the bottom? Thanks for the help everyone.