They are a tad low, and may have some contribution. The phosphate may also not be as low as you think. It is a big coralline stunter. What kit did you use?
How would you describe your skimmer? Highly effective? Elevated organics can also stunt coralline and other calcifying organisms.
These articles may help:
Solving Calcium and Alkalinity Problems
http://www.advancedaquarist.com/issues/nov2002/chem.htm
Phosphorus: Algae’s Best Friend
http://www.advancedaquarist.com/issu...t2002/chem.htm
Magnesium
http://www.advancedaquarist.com/issues/oct2003/chem.htm