Must modifications on a Reefer?

[Geo_6]

Hello,
I am about to set up a new tank (Reefer 250) what are the must modifications (if any) that you would recommend prior to filling the tank with water, live rock etc..?
I saw some info on gate valves for example. Any recommendations? greatly appreciated!

 

[Ortizdrz]

Gate valve on drain.
Strong enough return pump to handle few valves for future mods.
I also did away with filter socks and got a fleece roller