Here's the link to the MACO distance learning class: http://www.reefs.org/maco/index.php . For the DIY calcium reactor course, click on the DIY Acrylic course taught by Brian Ferguson.
A FWIW, since I don't think some folks understand the real point of fergy's MACO course.... It is more than just slapping together your own reactor. It is an education in methods and techniques to enable you to gain skill working will acrylic. The lessons learned in the course will enable you to build much more than a calcium reactor once you've finished.