The Under Current® XL13 and XXL13 systems are ideal for large-scale commercial growers. With the patented Sub-Current Culture® circulation method, growers can now improve operational efficiencies and overall yields. Sub-Current Culture® (SCC) technology utilizes negative water pressure to recirculate highly oxygenated nutrient solution through the plant’s root zone. This continuous fluid motion supercharges the nutrients with dissolved oxygen, creating hyper-aerobic conditions perfect for explosive plant growth. High levels of aeration and constant circulation optimize plants nutrient uptake capacity. This action conserves nutrients, water and necessitates less frequent nutrient change-outs. 30 inch plant centers with recommended growth time of 3-5 weeks. The Under Current® XL13 & XXL13 Systems Includes: 13 gallon Blackout Series growth modules, 3 in manifolds, 3 in UC Spin Tight Bulkheads, CCH2O 8 in Heavy Duty Lids with Port Hole, CCH2O Heavy Duty 8 in Net Pots, Danner Mag-Drive Return Pump, Premium Linear Air Pump(s), 9 in Air Diffuser Disc, Aqua-Pore Air Diffusers, Air Distribution Manifold, Air Hose, In-Line Filter(s), Adjustable Float Valve with Reservoir Adapter Kit, Drain Valve, Chiller Adapter, Garden Hose Drain Adapter, Cultured Solutions VEG A/B. These items are drop ship only.