OK...I finally got a reply from Fox Farms.

They told me that Big Bloom does not have enough phosphorus in it to use as a stand alone fertilizer when your plant is flowering, but Tiger bloom and Grow Big both have have the necessary micronutes.

You can use Big Bloom in combination with Tiger Bloom.

Big Bloom can be thought of as a catalyst, and it can be used the entire plants cycle, on new plants, and on plants that are not doing well.

So, I guess the Big Bloom is simply a worm casting/bat guano tea. Ya learn something new every day. :thumbsup: