Yep. You guys beat me to it. Here's Cecil's reply:
The additive is Astaxanthin and you can get a bag of feed from Aquamax with it already added for just a little bit more in price. It's known as Aquamax grower AX 5D19. You have to special order it and it's seasonal. Interesing thing is the pellet size is between a 5D05 and a 5D06.
I doubt that Cecil had to order 4,000# of it, maybe that's their minimum batch weight and once it's made you can possibly order it per the bag?
No, just ordered a bag at at time, but it is seasonal. Can't get it in the winter.
