What Size Do You Like for Reef Sump in 4x2x2 tank Stand?

[Todd]

I would also consider an external pump - it transfers less heat to the tank. When doing this remember you will need to plan room for your pump AND your plumbing. When I did mine I had planned for a external valve to isolate the pump, but I ran out of room so I had to scrap that plan.

Also some people have been saying that taller is better, but this depends on how tall your stand is - if your sump is too tall and you are using an insump skimmer it could be too hard to remove the skimmer from the sump and stand to clean / maintain it. (or the collection cup in my case.

I would definatly include an ATO, as well as baffells to prevent microbubbles from entering your display.