It's unfortunate you dosed your tank already.
I assume you have dino's in your tank since your thread is in the algae section and you mentioned them, but it's not totally clear from your post.
Can you post a full tank shot as well as a full set of test numbers? Especially PO4 and NO3. What has the history been for PO4 and NO3?
Please read this thread:
Dinoflagellates – Are You Tired Of Battling Altogether?
Well said....I wish that thread would be shut down and the first post should have a warning: DO NOT READ
+1
To say the least. Hmpf.