Sump Design

[Richer]

I'm putting together a sump for my 30 gallon tank. Here is what I'm thinking of doing:

First one:


Second one:


I was going to use a 30 gallon tank... but I couldn't get it to fit in the tank stand, so I'm using a 15 gallon tank that I had laying around.

My ultimate goal here is to eliminate micro bubbles while having the largest possible refugium. I'm probably going to put about 600gph through this sump. Which one would you choose? Any other suggestions?

Thanks!
-Richer