i am just building a new 180G (dual overflow) reef setup and i have a 1262 and 5000+ (both Eheim) pump for each return . the 1262 is obviously with better flow, more quite and less vibration than the 5000+. what i found is even with 2 pumps i still don't get the flow i want. imho i think u should get 2 1262 if u want to run the reactors at the same time. just my 2 cents.