did years of side by side testing of nutrients,, in the early 2000's to 2005...gh nutes are very effective, best yields to cost was with gh maxi series,, simple 1 part grow, 1 part bloom, but i found in the first 2=3 weeks of flower to use both half grow ,half, bloom,,or u get early yellowing.. by mixing the 2 then go to full bloom weeks 4- finish works great.. the gh nova series is also a great nutrient but a bit more expensive.. dyna gro, fox farm, and plant life wer all top 5 nutes, botanicare,advanced, wer ok but not in the top 5.. ive heard good things about canna but havnt tested it and i dont waste money testing nutes anymore.. i use gh maxi and nova,mostly maxi but use nova once in a wile on certain strains that are picky...my testing base nutes only,, then i tested adding the bloom bosters,,, the only one i found to really do anything was the powder form koolbloom,,not the liquid.. the one used for the last 2-3 weeks the powder koolbloom adds size and makes buds ripen 4-5 days sooner than w/out the additive.. most additives seemed to be a waste of money if u use the base nutrients correctly,, especially with the 3 part nutes,,almost all 3 part nutes work well once you figure out what the strain your growing likes,,each strain likes a different n-p-k and ppm,,so lots of tinkering but once u get the mix wright,,,,stand back and watch em grow....so all nutrients work,its up to each person to decide whats best for them,,3 part for tinkerers who really want to get it wright,,1 part for simplicity,,,or turn the 1 part nutes into a mix of the2 for better results.. btw go easy on all nutrients directions on the bottle,,start with less and use more if needed,,, many nutes want u to use more to sell more,,but u end up burning your plants using the full strength... also ppm is a big thing,, go to high,,,burn.. go to low,,,yellow or a list of deficiencies.. find the ppm that fits your strain and raise it gradually in the flowering stage, grow well n be well to all,,,,good luck