I would have to agree with a few of the others and say Ca Rx. Trying to keep the Alk/ Ca levels up would be tough without it.
My new 90 gal is just starting up, it has 2 6055's (AquaSurf should arrive today) and a Vortech wireless. My return pump is a Eheim 1262, but it goes through alot of bends and my chiller before ever reaching the tank. As soon as its aquascaped I'll post a few pic's and let you know about the flow. So far the Vortech is on the left side and I have one of the 6055's in the right rear corner pushing diagonally. Second may go on the side of the overflow, not sure yet. UPS is holding up my progress!