Current Culture H2O -- RDWC Hydroponic Systems
Current Culture H2O is the leading brand in recirculating deep water culture (RDWC) hydroponics, best known for their Under Current system -- the most widely deployed commercial RDWC platform in North American indoor production. Their systems are built on a central reservoir management philosophy: all individual growing sites connect through a sub-current recirculating loop to a single control reservoir, allowing pH, EC, and dissolved oxygen to be managed for an entire multi-site system from one central point. The result is the operational simplicity of a single-reservoir system with the per-plant control and water volume stability of an RDWC configuration.
The Under Current System
The Under Current (UC) and Under Current Pro (UCP) systems use a below-the-bucket manifold loop that recirculates nutrient solution continuously through all grow sites and back to the control reservoir. Unlike top-fed RDWC systems that pump solution down from a central reservoir, the Under Current's sub-current flow keeps nutrient solution moving through the root zone from below -- creating consistent dissolved oxygen levels and uniform nutrient concentration at every site regardless of how far it sits from the control reservoir. Available in configurations from the UC 4XL (4 sites) to the UC 16XL and larger commercial configurations, the Under Current Pro line scales to commercial production with simplified maintenance across high plant counts. For a complete explanation of RDWC principles, see our guide on types of hydroponic systems.
Current Culture CropTop Drip System
In addition to their flagship RDWC line, Current Culture produces the CropTop drip system -- a top-feed drip configuration that uses Current Culture's reservoir and plumbing infrastructure with above-canopy drip emitters rather than the sub-current recirculating loop. CropTop systems are designed for growers who want Current Culture's reservoir quality and build standards in a drain-to-waste or recirculating top-feed drip configuration -- popular for coco coir and rockwool grows where the drip-irrigation approach suits the growing medium better than full-submersion DWC.
Nutrients & Accessories
Current Culture also produces their own nutrient line (Cultured Solutions) formulated specifically for the high-oxygen, recirculating RDWC environment their systems create -- clean, chelated formulations that stay in solution well in recirculating loops and work well alongside popular programs like Athena and General Hydroponics. The air pumps and diffusers, control reservoirs, and replacement components for Current Culture systems are available here alongside the complete system configurations. For sizing and configuration guidance for commercial builds, contact our team at 888-815-9763.
Current Culture FAQ
What makes the Current Culture Under Current different from standard DWC?
Standard DWC manages each bucket independently -- pH and nutrients are adjusted per site. The Under Current connects all sites through a below-bucket sub-current recirculating loop to a single control reservoir, so the entire system is managed from one point. The sub-current flow keeps nutrient solution moving through the root zone continuously, maintaining consistent dissolved oxygen and nutrient concentration at every site regardless of position in the system. The result is DWC simplicity at the management level with RDWC-level consistency across all plant sites -- the core advantage that makes Current Culture the preferred RDWC platform in commercial operations scaling beyond 4-8 sites.
What size Current Culture system do I need?
Current Culture systems are available from the UC 4XL (4 growing sites) through the UC 16XL and modular commercial configurations. Match site count to your plant count and facility layout. For hobby operations running 4-8 plants per cycle, the UC 4XL or 8XL provides the full RDWC benefits in a manageable footprint. For commercial operations with 12+ plant sites per room, the UC 16XL and multi-unit configurations with shared control reservoirs scale accordingly. Current Culture also offers facility layout design consultation for large commercial builds. Our expert team can help configure the right system for your footprint and production goals -- call 888-815-9763.
What nutrients work best in a Current Culture RDWC system?
Current Culture's own Cultured Solutions nutrient line is formulated specifically for high-oxygen recirculating systems and is the recommended pairing for Under Current systems. General Hydroponics FloraSeries and Athena Blended Line are also widely used in Current Culture systems with good results -- both are clean, salt-free formulas that remain stable in recirculating solution. Avoid heavy organic nutrient programs with high microbial or particulate content in any recirculating RDWC system -- these can cloud the solution, reduce dissolved oxygen transfer, and increase biofilm buildup in the recirculating loop. Always use clean, filtered water and maintain reservoir temperature at 65-72 degrees F for optimal dissolved oxygen levels.
How do I maintain a Current Culture RDWC system?
Change the full system reservoir every 7-14 days depending on growth stage and plant feeding rate. Top off daily with pH-adjusted water to maintain reservoir volume. Check pH and EC daily from the control reservoir -- in a properly functioning RDWC system, all sites will reflect the control reservoir values within a narrow range. Clean the full system between cycles: drain completely, flush all lines with a dilute hydrogen peroxide solution, rinse with clean water, and inspect all fittings and recirculating connections for scale or biofilm buildup. Current Culture publishes detailed maintenance SOPs for their systems; our expert team at 888-815-9763 can walk through any maintenance questions.
What is the difference between the Under Current and CropTop systems?
The Under Current is an RDWC system -- roots grow in aerated nutrient solution with the sub-current recirculating loop maintaining continuous flow through all sites. The CropTop is a top-feed drip system that uses Current Culture's reservoir and plumbing infrastructure but delivers nutrients from above through drip emitters rather than through a sub-current loop. Under Current is the right choice for growers who want pure RDWC with roots in solution. CropTop is the choice for growers who prefer a drip-irrigated approach on growing media like coco coir or rockwool, where roots grow in a medium rather than floating freely in solution. Both use Current Culture's high-quality reservoir systems and are available in scalable configurations.
