no you do not i have been using it for 5 crops , use what the book ses far as dose but you can use less than half and still do veryyyyy well , mix well . also fish mix is not required for good products if used in bud will make it taste like fish poo ... but if you like try one plant give it too it . I never ph my plants are great . dont pay attention too ppm thats not a issue either . U will soon be growing the best buds in town good luck.