Preventing Algae in Ultrasonic Humidifiers for Nepenthes

Keeping Humidifier Tanks Algae-Free

A grower runs an ultrasonic humidifier 24/7 for Nepenthes pitcher retention. The clear tank grows green algae under grow lights. They seek solutions besides wrapping the tank in foil.

Expert Solution

Jeff Dallas: Use distilled water in the tank. Clean the tank thoroughly with bleach first, then fill with distilled water. With zero nutrients, algae cannot grow. A ZeroWater filter (which removes nearly all dissolved solids) also works—purified water stays algae-free, while the unfiltered top reservoir still grows algae.

Why This Works

Algae need nutrients (minerals, organics) to grow. Distilled/RO/ZeroWater water lacks these, starving algae.