My alkalinity is at 7.4 dKH which is the value you are referring to reefer? How much higher do you keep your alkalinity at Jim? Right now my water flow is pretty good. Alot better than it used to be. I got an Iwaki MD20RLT coming from my sump hooked up to a SCWD and I'm gonna be adding another one in a closed loop pretty soon when I have the time. I've got all the parts and pump, I just gotta put it all together. As for magnesium, I've never tested for that. What do you usually keep yours at? What supplement do you use to keep it where you want it?

Also, what about the 10K XM? Any faster growth out of them compared to the 20K that you've noticed yet? They're supposed to be even better than the Iwasaki for growth right?