SensiBloom A&B is a high quality 2 part nutrient solution. SensiBloom A&B is formulated with R.O water and chelated nutrients. SensiBloom A&B already has fulvic and humic acids in the bottles. These acids assist in root development, pH stability, and yield enhancement. SensiBloom A&B is a true 2 part nutrient, so they are to be used in equal parts. Dosage 4 ml. per liter. Price reflects cost of 2 bottles.