Do I see a pattern here? Christy didn't you just replace your sandbed? And Brad didn't you recently rearrange the tank. Delphinus you mention an outbreak after sandbed movement. I wonder if moving stuff around, kills off some semi-nasties and frees up food sources for Dino's. I don't know I'm just throwing out a theory here.
Also Delphinus, you are right, dino's are a form of red tide (see here
http://www.geo.ucalgary.ca/~macrae/p...agellates.html ) . I do know that red tide is more prevalent near pollution sources, ie mills, sewer outflow ect.