Potassium Sulfate — Water Soluble Potassium Source

Potassium Sulfate (SOP) — Chloride-Free Water-Soluble Potassium for Hydroponics & Fertigation

Potassium sulfate (SOP) is the preferred potassium source for professional hydroponic, greenhouse, and fertigation programs. Nitrogen-free and chloride-free, SOP allows growers to supply potassium independently of nitrogen — essential for maintaining precise N:K ratios during fruiting and finishing stages without driving unwanted vegetative growth.

With 50–53% K₂O depending on grade, SOP is the highest-analysis chloride-free potassium fertilizer available in water-soluble form. Custom Hydro stocks multiple grades to match your system, crop, and certification requirements.

Why SOP Over MOP

• Chloride-free — no chloride accumulation in recirculating systems or sensitive soils
• Nitrogen-free — precise K control without affecting N:K ratio
• Sulfate sulfur co-delivered — 17–18% S supports protein synthesis and enzyme function
• Low salt index — safer for sensitive crops and high-EC environments
• pH compatible — neutral to slightly acidic; no adverse pH effects in solution

Available SOP Grades

• Organic SOP Standard Fines 0-0-50 + 17% S — OMRI certified; fine-screened for rapid dissolution
• SOP 3IX 0-0-53 + 18% S — highest-purity crystalline SOP via ion exchange; ultra-low chloride
• Haifa SOP BIO 0-0-52 + 18% S — organic-certified; EU compliant
• Haifa SOP GG 0-0-51 + 18% S — greenhouse-grade; fast dissolving; acidic pH