... .Water soluble 3. Alginic Acid=8-15% Natural Seaweed Extract Powder, 100% water soluble, organic fertilizer China patent no.: 03112663.6 Product character ... , water soluble, pH=8-10Main ingredient: Alginic Acid: 8-15%, organic matter≥50%, N≥0.5%, P2O5≥3.0%, K2O:18 ... /DHydrargyrum(Hg)N/DChromium(Cr)N/DArsenic (As)N/D Natural Seaweed Extract Powder, 100% water soluble, organic fertilizer