SUPERthrive Pro-TeKt in a 55-gallon drum is a special order item designed for large-scale commercial growers, nurseries, and agricultural operations. This bulk size offers a cost-effective solution for those who use Pro-TeKt extensively. Pro-TeKt is a silicon-based plant protectant that strengthens cell walls, making plants more resistant to various environmental stressors. Lookin... https://www.hydroponicstown.com/dgtek-550-superthrive-pro-tekt-55-gal-special-order-item