Having trouble getting your Orchids to re-bloom? AlgoFlash Orchid Fertilizer (4-6-6) ~ with magnesium and micro-nutrients ~ is a concentrated liquid fertilizer containing all of the necessary nutrients and magnesium to stimulate generous flowering on Orchids with no additives which can harm tender Orchid plants. One cap full makes a full gallon! Sold in 300 ml/ 15.5 oz size bottles. Makes 10 gallons of fertilizer.