On the RO/DI questions I would send those to Russ at Buckeye. Aqua C Skimmer with a mag three will be to big for a 30 plus noisey and sit on the side of the tank. Since you have a sump I would go with an insump skimmer, out of sight. Oh yea welcome back. I think a 250w would be too much light/heat for a 30.