5lb bag of MKP cost me $17 shipped. treats 4540 gallons. Third of a penny per gal.You know ive never really noticed a weight gain that justifies the price of a p/ k boost in flower. Ive used moab....ionic boost....canna....koolbloom and quite a few others. Maybe its just me. I did notice a slight increase i weights with Bloomabstic and Greenfuse and some H&G products but it prolonged flowering and the gains were slight compared to what tose tiny bottles of concentrate costs.