Sorry for the lack of updates...
No problems with the rack at all.. I bought them from a local distributor. They are Cardinal brand racks and I had then over rate the load just in case. The load on the 6 pads is about a 10" square area (Plywood under base) so I don't think there should be any issues with the concrete at all.
I can isolate them as each tank has it's own shutoff valve and I can just attach a canister filter to one if needed.
And no problems at all with the central sump.
I have recently just decided to give up on salt though (Too many recent deaths of some rare eels and the female shark) and I cannot take anymore. I am pretty sure they all got poisioned from over spray of "Food safe" cleaner solution from my local sea food store as only the animals who eat the shrimp and smelt got sick and later died without any good reason.
So I was going to take it all down and sell the hardware but I think I am going to convert them to fresh and get come shovel nose cats and what not. At least get some more enjoyment from this system.
