The Lucas formula is a simple method for mixing nutrient solution in proportions that are tailored to the cannabis plants nutrient uptake profile. You can mix a Lucas formula from any nutrient brand, but I use the three-part Flora line General Hydroponics (Grow, Micro, Bloom). One of the first things you'll notice when applying the Lucas formula with General hydroponics flora line is that you dont have to use any of the Grow formula, And this is not a mistake. The Micro part of this three-part line has all of the Nitrogen a garden needs, and since the Lucas formula is a "less is more" strategy, you can skip using the Grow part altogether. You should also change your reservoir once a week and top it off with pH-adjusted water daily. This feeding system works extremely well in hydroponics systems because of the low ppm of the nutrient solution it is unlikely to clog lines and or build up salts. Also, since there is no organic element to this mix it give a great opportunity to use hydrogen peroxide (H2o2) in your water. The hydrogen peroxide will kill off any algae or fungus that can grow in a reservoir, and it also releases oxygen to the root zone. Great results can be achieved with this simple mix, all you need are three things: GH Micro, GH Bloom, and Hydrogen peroxide. I found my results nothing less then spectacular.