I received 3 filter cylinders, Mag 7, and manifold in today from Jeff at Life Reef Systems, besides my sump/refugium,skimmer, I am still impressed with Jeff's worksmanship, the man takes pride in his work and it shows in construction, I will be pulling the Sump,Refugium, return pump out of stand to do some spring cleaning under stand and also to clean out Sump/refugium as well, the golden algea left alot of gunk in my sump, skimmer, and I need to clean out all detritis as well,I really didnt understand the size of these cylinders and only ordered a 1/2 gal of Premium ROX 0.8 Aquarium Carbon and 1 lb. of GFO, I will be mixing the 2 as these are flow through and not fluidized canisters, along with everything else I will do at least a 30% water change after I replace the filters in my RO unit, I'll have pics of tank and under stand this weekend, I do have coraline algea on glass and its spotting alot of the rocks,I will also get the corals perm. glued to rocks and off the frag plugs.