Aptus PeakBoost is a better option than many combined P/K boosters because it allows the targeted application of phosphorus when and where the plant needs. Often when P and K are added in high quantities at the same time, one or the other remains unused in the medium. This can cause antagonism, chemical binding, and nutrient lockout. PeakBoost contains organic acids that can help to adjust pH-down for your nutrient mixture. PeakBoost is 100% soluble in water and doesn't leave residue in reservoirs and irrigation systems.