Here's an update on my phytoplankton efforts. I think I'm having more success now. This is an example of what I'm currently brewing. This batch has been going for 2 weeks now and still has a rich, green colour. (not the yellow-green that I was getting before).
Although I've played with the recipe, I think the improvement is because of:
1) Daily shaking to prevent anything from settling on the bottom.
2) 2nd and 3rd time using the same bottles. It's possible that the bottles weren't absolutely clean the first time I used them, but now they are behaving better.
I've manipulated the amount of fertilizer in the mix, but get very similar results no matter what I do.

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400 gal reef. Established April, 2007. 3 Sequence Dart, RM12-4 skimmer, 2 x OM4Ways, Yellow Tang, Maroon Clown (pair), Blonde Naso Tang, Vlamingi Tang, Foxface Rabbit, Unicorn Tang, 2 Pakistani Butterflies and a few coral gobies
My Tank:
http://www.canreef.com/vbulletin/showthread.php?t=28436