you can mix yes, but be very careful as i have found using humbolts stuff it some times does not go well with other brands, i used the gravity stuff a few grows back and mixed with farmfox, burned my stuff bad, when i used it with other humbolt nutrients the buds were fine, so if you mix i would use less and test it on one plant if you can. it is just i have been there before and hate to see another grower ruin the harvest by a mistake i made, hope this helps