It might seem good to run 30 amp lines, but it is not! Outlets are rated for 15 or 20 amp for our pumps and lighting and such.. a 30 amp line would be for a dryer or something bigger, AC unit...
Alright, I'm not licenced yet outside of the military, so I'm likely wrong... Yet, isn't the breaker rated such to protect the wire from overheating from excessive I2R losses at higher currents? A 30A breaker is rated for wire no smaller than 10 AWG for this reason, is it not?
If something faults as such to create a short, will not a 30A bkr still protect the system, or are you saying that the smaller equipment would not be able to trip a 30A Bkr even when faulted?
As for the GFCI outlets, I have one installed next to my tank so as to allow for that to trip the system while leaving the rest of my home's electrical intact. My tank is all connected to one 20A breaker via two GFCI protected outlets; granted, my system is small enough that I'm not going to have to worry about coming close to maxing that out. (running about 11A total)