by T off the return, you are skimming and/or chilling app 50% of the water only
skimming will be less effective & chiller will kick in more often
for optimum performance, skimmer & chiller feeding pump(in) should place 1 compartment before their "out"
to prevent microbubbles, skimmer "out" should place 2 compartment before return
if do correctly, 1 compartment should be sufficent
i place my feeder pump in the first compartment, feeding to my chiller, then to my skimmer then back to the 2nd compartment
cheers