Cool! Thanks guys, sounds like I'll be fine with just one circuit, so two will be overkill!
Chris, gravity feed can suck especially when it has to travel to the otherside of the room. Yes, the air being pushed at the sump is amazing, just putting your hand over it really quiets it, but you can really feel it pushing...

You'll have to come over again some time to see it flowing!
As for your 600, you have it draining almost straight into your sump, 2 2" pipes is more than enough for me, but I have them T'd together which restricts the flow, I went to the 3" to help reduce the back pressure and let the water fall from there. If you look in the cap (they are removable) at the drain, it looks like one hell of a water ride! LOL!
UPDATE:
Tank is already half filled, I forgot we went with a 125g/day unit, I thought it was 75... So tank should be filled tonight and ready for sand and salt. Rock got treated last night, but not sure how long to let it sit before putting it in the tank, and do I need to do anything to get rid of the Interceptor from the rock?