I have just ordered a proclear wet/dry 75 and a coralife skimmer but i think it should still be fine if the skimmer is after bio-balls. But thanks for advice anyway. And to BellaNavis, I just ordered a sump, sorry. But I'm glad you offered and I wish you luck with selling them. And to everyone that helped, THANK YOU!
p.s. from now on I'm done with this topic and the other one I made about skimmers alone. So no need to help now, but thanks again if you did.