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Water & Reservoir

How often should you change DWC water?

The answer is: 7–14 days

Stay closer to 7 days with mature plants, high nutrient demand, or a reservoir that is becoming less stable.

How often should you change DWC water?

Why

A full DWC or RDWC reservoir change every 7 to 14 days is a practical baseline. Plants do not remove every nutrient at the same rate, so repeated top-offs can keep the EC looking reasonable while the actual nutrient balance drifts. A complete change resets that chemistry and removes accumulated residues. Stay closer to 7 days with mature plants, heavy feeding, unstable pH or EC, cloudiness, odor, or root-zone concerns. A clean, stable, lightly loaded system can often run closer to 14 days.

What to remember

  • Use 7 to 14 days as the baseline for a full reservoir change.
  • Stay closer to 7 days with mature plants or high nutrient demand.
  • Top-offs can maintain EC while the nutrient balance still drifts.
  • A complete change resets the reservoir chemistry and removes accumulated residues.
  • Unstable pH or EC, cloudiness, odor, or root concerns are reasons to change sooner.
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