A few more observations, I have a Stylophora that a friend gave me, we keep them under the same ligths, he has not done a water change since December and I have done multiple changes, his has outgrown mine by a lot! He basically broke it in half and gave me a piece so the same coral. It should be noted he does feed his corals and I don't, which could be the obvious difference in growth but my point is his water quality you would suspect is not as good as mine, or maybe our definition of "good water" is off base. So, maybe nitrates is not really the molecule that is responsible for growth but likely what ever process leads to higher nitrates also leads to other waste material in the water that is converted to coral. Studies have shown if you exclude algae eaters from a area of a healthy natural reef you will have algae over growing the corals in a few weeks. Not sure what all this means but the system is way more complex then the surface that our test kits scratch.