I am currently in the process of setting up a 2 DT setup. I have a red sea reefer 450 (92g) currently set up and running on temporary filtration for a short time. I have a 150g DT that I plan on drilling an overflow box into today. I am looking for advice on the sump. I plan to run both tanks to 1 common sump. I have a Geo's Reef Su46rd-pro, total volume of 44g that I could use or I can use a 75g aquarium as the sump. I am torn as the geos reef has many nice features but I am worried it will be too small for the combined system volume. I am wondering if I should just attempt to sell the Geo's Reef sump and use the 75, Use it and be careful of drain down, or do some hybrid and drill the geos reef with a bulkhead and have it gravity overflow into the 75g with a return pump stationed in the 75g.