I know this wouldn't be the most efficient way to set up a SPS and an LPS separately due to water likes, etc., but how much trouble am I looking at if I connect the two tanks (125 and 120) with piping between sumps and force flow through each. My reasons are space related, primarily (noise weighs in, too). I figure I could upgrade my MR2 to an MR3 to handle the entire system. Then, with a nice sized calcium reactor, I could maintain both systems with one set of controls. The chiller is 1/2HP, so I think it would do fine on the entire system. I have another chiller I may add as a redundancy if the big chiller can't keep the temp down, but I think the 1/2HP will be fine. Water changes would be larger volume, but out of one tank instead of two. My main reason for wanting to build separate systems (aside form the way a 250-300 gallon tank sounds to the CFO) was to put lower light over the LPS tank, as they don't currently appreciate the beams they get know. I figure it'll add to the amount of drainage space in the sumps, too, as they'd be tied together. I could always separate them if needed, but what negatives would I be getting myself into? Assume all corals/fish are strictly quarantined to reduce the possibility of added predators/diseases.