@Dabber - pulled this form the greenleaf faq
"Also, a few products cannot be mixed in with the main product, for example Sweet Candy has high amounts of carbohydrates/sugars, so it can cause fungus/mold/rotting issues if mixed in with the main formula, or in certain growing methods like RDWC or recirculations systems. So this is a standalone product not mixed with main formula, and offered separately, however it is completely options and not necessary."