copepods question

[Calgarynewtankguy]

So I was at a local fish store and see a bottle of live copepods for sale. from what I read these were good to introduce into a refugium. So I went ahead and bought some. when I got home I put the whole bottle into my refugium (which has cheato algae) but not realizing, i dont have any sort of screen or filter before my main return pump.

what is there to stop these copepods from entering my DT and then back down into my filter socks??

did I do this right or was it a complete waist?