Yes I did tie the drains together in one line and did the same with the returns. The CLS had it's own suction and returns.
The way I am going to set it up this time is I'm going to make the returns inside the over flow drains, so each box will have two drains, I will tie them all into one drain. I will then eliminate the suction on the CLS, and put it on the sump that I am getting that is already drilled. Then the CLS ports will be my new returns.
The only pump I will leave in the sump is the one for the skimmer. Unless I think the Dolphin pump can handle running returns and it. I would much rather get all internal pumps out if possible. At most a MaxiJet for a Phosban reactor.
I have a 30gl for a sump on it now, I was worried that the drains wouldn't be able to keep up with the Dolphin but now I changing the sump to a 75gl I think that will help with keeping up with the pump. When I get the sump I will have to add the baffles, it's already got 3x1.5" holes drilled in the bottom corner.