I built a Ca Reactor,

[BCOrchidGuy]

But I won't post pics cuz too many people have built them, mine is pretty simple, just a 2ft tall 4 inch dia tube with a cap on it. The plumbing is simple, input goes in the bottom, and blows up through a screen and Carib Sea ARM, in the center of the screen a 1/2" PVC pipe goes up with in a few inches of the top, that is where the water returns to the pump. In the cap there is a nipple for the effluent to return to the tank. The water goes in the bottom of the tube on one side and returns to the Mag2 on the other side of the pump. The entire foot print of it is 7 x 10 inches and I think I figured out how to get it close to 7x8... so I may change some things.

ARM says to have your pH around 7.5, mine shows 7.48, I have 20 bubbles/min through the counter... it has only been running for 2 hours so I can't tell you how the Ca levels are in the tank yet. But, I'm one happy camper.

Thanks for all the help suggestions and pictures folks, it really did make the job..... almost simple.