Jackson I agree phosphates do affect coloration to some degree. You brought up a good point on how to monitor the phosphates.
I have four differant Torts. Three with differant shades of green tint. I'm convinced there are many similar Torts going around being lumped together and called Cal Tort or ORA Tort. I have one that actually appears mostly green with just blue on the tips of each coralite and another one next to it that is mostly blue with just a tiny hint of green showing. I personally think there are many strains floating around, similar enough to be called a Blue Tort, but differant enough to call out the differences.