I've run my 90 gal for 4-6 weeks without a skimmer. I've been having algae problems. So i broke down and purchase a Coralife Super Skimmer (rated for 125 gals). I'll let you know if it reduces the algae problems. By the way I have to run this a HOT. Does anyone know how to reduce the microbubbles. I read the 101 pages on another post.