Under Current Hydroponic System FAQ

Under Current Frequently Asked Questions

System Setup

  • Can I integrate a water chiller?
    • Yes, Refer to instructions
  • Can I integrate a nutrient auto dosing system?
    • Yes, Visit the Automation section on our website for more information
  • Can I have my air pump(s) on the floor?
    • No
  • Can I have my air pump(s) in the room with supplemented CO2?
    • No
  • Can I run multiple Under Current® systems with one air pump?
  • Can I operate my Epicenter remotely?

System Operation

  • Is it possible to over-aerate my Under Current?
    • Yes
  • Do I need to use Reverse Osmosis (RO) water in my Under Current?
    • Yes
  • Should the Air Pump and Water Pump run 24/7?
    • Yes
  • How do I find my total system volume?
    • Reference the Systems Specifications on the Under Current Products page @ cch2o.com
  • Where should I set my solution level?
    • Bare Root: Top of root crown
    • Rockwool/Cube: Just below base of RW/cube 1/4-1/2” below NET POT planting deck.

Grow Media

  • What grow mediums are recommended for use in the Under Current?
    • Expanded clay pellets
  • Can I use soil or coco in the system?
    • No
  • How do I prepare my grow media?
    • Refer to manufacturer’s recommendations
  • Can I reuse my grow media?
    • Refer to manufacturer’s recommendations.


  • Should I transplant sparsely rooted clones into the system?
    • No

  • Do I need to top-feed newly transplanted clones?
    • No, when clones are well rooted and planted as directed. Refer to Water Level info
  • Can I move plants from an 8-gallon system to a 13-gallon system?
    • Yes
  • Can I veg in the dual/quad lids and transplant to single lids?
    • Yes, refer to Veg Guidelines.
  • Should I dim/raise my lights after transplanting?
    • Yes, generally, for the first 24-48 hrs.

Nutrients & Change Outs

  • How frequently should I change my nutrients?
    • Every 7-10 days
  • Are Carbohydrates/Sweeteners, Enzymes and Beneficial Bacteria recommended in the Under Current?
    • No.

Nutrient Schedules

  • Can I add weeks to my feeding schedule?
    • Yes
      • To extend VEG repeat week 4
      • To extend BLOOM repeat week 5

pH Adjusting

  • Can I use both pH UP and pH DOWN if I’ve overshot my desired pH level?
    • No, dilute with water and/or wait at least 24hrs.


  • Do I need to flush my system between change-outs?
    • No


  • Do I need to fully disassemble my system to clean it?
    • No
  • What should I use to clean the system?
    • Refer to Sanitization Process.
  • Do I have to replace any parts after harvest/cleaning?
    • Typically No, when proper the Sanitization Process has been completed. *Though some growers will replace net pots and air stones as needed.

Plant Maintenance/Trouble Shooting

  • Should I root prune?
    • Yes, refer to info
  • If my plants have stalled and haven’t grown for weeks, will they recover?
    • Possibly, refer to Troubleshooting.

System Upgrades & Expansion

  • Can I expand my Under Current system?
    • Yes, contact us.
  • Can I upgrade my Water and Air Pump(s)?
    • Yes, contact us.