Drain would work.
Unfortunately we have no AC, a constant source of disappointment to my girlfriend haha. That said my apartment never really gets out side of the mid 70's especially in the room where the tank in, and worst I've seen so far is high 60's/low 80's on a few extremely hot or cold days (one of the many reasons I love San Francisco).
So you'd throw the chiller and reactor returns in the sump chamber, where I am at least currently planning to keep the heater as well, or would you go with the drainage chamber pre-filter sock?