Recommend a bloom booster to use in conjunction with Bushmaster and Gravity?

I'm using Dyna-Gro Foliage pro and Protekt. I have the Mag-Pro for flowering. In soil, under 1200W HPS.

Can anyone recommend an additional supplement to enhance the flowering?

again this comes down to preference. So this thread could go on for years.
if you want sweeter tastes try topmax & bio-heaven
if you want bigger buds try pk13/14, shooting powder or overdrive
if you want weight try that shit called rox
Better yet. do a google search on Bllom boosters and figure out which one will work best with your needs and wants. But I would be careful adding stuff to Bushmaster and Gravity. You might just see your plants go POOF right before your eyes, since those are bloom enhancers.

If you use gravity make sure you raise your lights a good amount and the feeding or two BEFORE using gravity, make sure you cut the ppm's down SUBSTANTIALLY. Else, as Lord Dangly Bits said, POOF!