I ordered copepods from here and I was wondering where should I add them? I have a 125 gal tank and a 40 gal sump with 15 gal refugium. I was thinking refugium but wanted to make sure that was best.
Yes, the refugium is the best place IMO. Best way to do it is when the pumps are off for a few minutes so you can give them a chance to settle into the fuge. Also it's a good idea to acclimate pods a little by temp acclimating and adding a little tank water a few times. Pods are resilient, but no reason to kill more than you have to.