1 or 2 overflows, closed system

[mm16]

I found the tank that I'm looking for, someone had ordered it then backed out now they are selling it at discounted price and its glass. It is 6ft long 2ft wide, and 3ft tall. My concern that it only had one overflow and its at the end of the tank because we are putting it in between a wall, to see from both rooms. It also has a drilled hole in the center bottom that is for a closed system which I don't know what that is. Is one overflow and a closed system ok for this size tank?

Thanks

 

[Bifferwine]

One overflow is fine for a tank that size, although odd that it's drilled that way -- usually when you get over 4 feet, you start seeing an overflow on each end. Regardless, it will still work. As for the hole on the bottom, I have no idea what you are going to do with that.