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Environment

Green slime / algae in reservoir or on media

Bright green film on the reservoir walls, on top of the growing media, or in the lines.

Commonly affects: All hydroponic crops

What you'll see

  • Green slimy film on reservoir surfaces
  • Green coating on coco, rockwool or net pots
  • Cloudy, green-tinted nutrient solution
  • Possible secondary fungus gnat problem

Likely causes

  • Light reaching the nutrient solution
  • Translucent or open-top reservoir
  • Nutrients spilled on the surface of media

How to fix it (step by step)

  1. 1Block all light — black plastic, paint, foil, or opaque tank
  2. 2Clean empty equipment using a suitable labelled method, observing contact time and rinse instructions
  3. 3Cover exposed media with a black weed-fabric collar
  4. 4Replace contaminated growing media if possible

Stop it happening again

  • Use opaque, sealed reservoirs from day one
  • Cover net-pot tops to keep light off the root zone

Need a second opinion?

Share dated photos, root observations, water readings and your mixing record so our team can assess the problem. Visual symptoms alone do not confirm a diagnosis.

Confirm the cause before treating the crop

Collect observations that distinguish possible causes

Record the first appearance of symptoms, the affected plants and whether old or new tissue is involved. Inspect roots, delivery and visible pests. Compare a healthy plant nearby. Record pH, EC, temperature and recent changes. Several causes may act together; the symptom title is a starting point, not a confirmed diagnosis.

Verify calibration and the complete mixing record. Product links explain nutrient roles; they are not instructions to use one bottle alone. Record your correction and assess subsequent growth because damaged leaves and fruit may not recover.

Escalate safely

Rapid wilting, collapse or spreading root symptoms need prompt checks of flow, oxygen and hygiene. Protect unaffected plants where practical and seek qualified diagnosis. Treatments must be registered for their intended crop and use and applied according to label, including harvest intervals.

When asking for help, provide dated root and leaf photos, water readings and mixing records. Do not combine nutrient changes with disinfectants or pesticides without compatibility advice. An online guide cannot confirm a pathogen or prescribe a universal chemical treatment.

Further reading

These sources support general cultivation guidance, not verified Nana Organics product performance. Current NaO instructions take precedence over another brand’s feeding schedule.