Seaweed Fertilizer, seaweed organic fertilizer. Used by spraying and irrigation / fertigation, or added to other fertilizers 1.1. Alga21ST High Potassium (seaweed extract powder with high potassium) China patent no.: 03112663.6 Product character: Black or brown powder,water soluble,pH=8-10.Main ingredient:Alginic Acid: 8-15%,organic matter≥50%,mannitol: 1-6%,N≥0.5%,P2O5≥3.0%,K2O:18-22%,I≥400ppm; ...