i have kept the ray aro mix for more than 15ys with no problems at all
i kept a black aro for 7yrs with a motoro and a leopoldi no problems
1 kept a asian RTG for 18 months with a pair of pearl rays and a black diamond (leopoldi) with no problems
as long as you are not sill and put a ray that has a much larger disk size than the lenght of the aro the aro will be fine
the LFS that lost aros eatern buy rays i bet they were not feeding the ray as much as it needed
rays need 2 x small feeds per day to keep them happy