I would T off the return to feed the fuge, clean water in the fuge is best
That's a LOT like I have my set-up.
With all due respect I have mixed feelings there. In my thoughts the fuge needs the "Dirty" water because you are indeed trying to grow Macro. It's sort of counter-productive to skim/filter the water and THEN send it to the Macro/Fuge. That's just my thought process and it's been wrong before but this set-up has served me well for 3 years now so it's not terribly flawed.