I just grabbed this Kent marine set up for.my 30g biocube. I have a nice assortment of corals and 5 fish amongst other things like urchin, inverts, shrimp, starfish and tiger conch. I've noticed some of my corals look a bit shrunk, nothing to severe, I do a 5 gallon water change every week like clock work, I have a protein skimmer which seems to suck and cant really get it dialed in, and I have the biocube filter retro fit where I has the stack containing floss up top, purigen in the second rack, and a bag of chemipure elite. 90% of my corals are thriving, I'm just worried about my magnesium and calcium levels. I dont have a test to kit and I'm sure in the last year this tank has been up and running that these 15 corals have stripped my water of essential nutrients. What do you guys think of this kit? Any suggestions for a different brand or something in addition to this kit? I'm hoping some of you guys can steer my inexperienced butt to a healthy thriving reef tank.