Science is often behind the real world and lab testing results are not always easily transferable to reality. That being said, in Randy's artical (
http://www.reefkeeping.com/issues/2004-05/rhf/index.php), unless I am misunderstanding, it seemed that raising alkalinity above nautral seawater levels had more effect on growth rates than raising Ca. That was a sterile environment - and there was no mention of coloration or any other measure besides calcification. I have held my Alk higher and Ca a little lower and this thread is making me reconsider that philosophy.