When procuring liquid humic substances, the most critical factor is the concentration of active ingredients, typically measured as Humic Acid (12%-20%) and Fulvic Acid (3%-5%). Ensure the product has a pH level between 8.0 and 10.0 for stability in alkaline formulations, or a lower pH if specifically designed for acidic soil compatibility. Additionally, verify the water solubility is 100% to prevent clogging in fertigation and drip irrigation systems. Check for organic matter content (often >150g/L) and the presence of chelated trace elements like Iron (Fe), Zinc (Zn), and Manganese (Mn) which enhance the biostimulant effect.