Roller Pumps have a very short life span in our world. You will have to keep changing the rollers out frequently and adding new ones. If your planning on sticking with a 12volt pump system I would just go with a Delevan, Sureflow, or FlowJet. I didn't even know you could get a roller pump in a 12volt. The only ones I ever looked at were driven by a gas powered 5.5 or 6hp engine. Here... Check this one out and you will see what I'm talking about on how to change out the rollers.
Before i got the air pump i used the Flowjet from northerntool it was good because they give you a waranty. 5.0gpm pump it's like $135.00 i think. I still have some for back up's