Sump Help

[Aquaria]

reason for the small return is the way the stand is it is very small and that design means the refugium is up front when u open the stand door now i was planing on doing a diy ATO have a 4g jug with ro/di above the return using a ridged airline for a gravity feed design (works like the automatic waterbowls for pets) for the guy that asked its a 10g tank for a 20g nano
now i could move a couple baffles to the return section and use the whole 5 x 9-3/4 area that holds the baffles now as the return.
an answer asap would be great as im leaving in 30 min or so to order glass and get parts for sump