Thermostat aquarium heater with safety shut off for 20L to 110L fish tanks
Thermostat aquarium heater with safety shut off for 20L to 110L fish tanks - 300W

Premium Thermostat Aquarium Heater ZY-188 Series for 20L to 110L Tanks

$12.99
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Create a stable and safe aquarium environment with the ZY-188 Series Thermostat Aquarium Heater. Each model features precise temperature control, rapid heating efficiency, and an automatic safety kill switch that shuts the heater off if overheating occurs or if the heater is exposed to air. The ZY-188 series is crafted for reliability, making it an ideal upgrade from low-quality heaters sold on discount platforms.

Every heater undergoes strict QC and QA testing to ensure long-term performance and safety. The shatter-resistant design, thick protective casing, and 1.5 metre power cable make this a dependable choice for home aquariums, desktop tanks, and breeding setups.

Your heater will be sent with the correct plug type based on your delivery address. For example, orders shipped to the UK will receive a UK plug.

Key Features and Important Notes:

  • What’s Included:
    – 1 × Thermostat Heater Unit
    – 1 × Power Cable (1.5 metres)
    – 1 × Safety Instruction Sheet
    ⚠️ Fully submersible heater
  • Built-in Thermostat:
    Maintains a stable temperature automatically for tropical fish.
  • Automatic Safety Shut-Off:
    Includes a safety kill switch that turns the heater off when exposed to air or if overheating occurs.
  • QC and QA Tested:
    Every unit is tested to prevent the failures common with cheap heaters sold on low-cost platforms.
  • Durable Construction:
    Shatter-resistant exterior designed for long-term use in freshwater tanks.
  • Correct Plug Included:
    Your plug type matches your shipping country automatically.
  • Warranty: 1 Year Warranty (T&Cs apply).
  • Safety Notice:
    Low-cost heaters from platforms like Temu have been reported to crack, explode, or fail within weeks. All Castle Dawn Aquatics heaters are QC and QA tested for safe, reliable performance. Backed by a 1-Year warranty.

Model Options and Tank Compatibility:

(All sizes converted to cm, inches, US gallons, and UK gallons)


  • 25W Heater
  • Size: 20 × 2.5 cm (7.87 × 0.98 inches)
    Tank Size: 20 to 35 litres
    • 20L = 5.28 US gal / 4.40 UK gal
    • 35L = 9.24 US gal / 7.69 UK gal

  • 50W Heater
  • Size: 20 × 2.5 cm (7.87 × 0.98 inches)
    Tank Size: 30 to 45 litres
    • 30L = 7.92 US gal / 6.60 UK gal
    • 45L = 11.88 US gal / 9.89 UK gal

  • 75W Heater
  • Size: 20 × 2.5 cm (7.87 × 0.98 inches)
    Tank Size: 45 to 60 litres
    • 45L = 11.88 US gal / 9.89 UK gal
    • 60L = 15.85 US gal / 13.20 UK gal

  • 100W Heater
  • Size: 23 × 2.5 cm (9.05 × 0.98 inches)
    Tank Size: 60 to 80 litres
    • 60L = 15.85 US gal / 13.20 UK gal
    • 80L = 21.13 US gal / 17.60 UK gal

  • 200W Heater
  • Size: 28 × 2.5 cm (11.02 × 0.98 inches)
    Tank Size: 70 to 90 litres
    • 70L = 18.49 US gal / 15.39 UK gal
    • 90L = 23.77 US gal / 19.80 UK gal

  • 300W Heater
  • Size: 32 × 2.5 cm (12.59 × 0.98 inches)
    Tank Size: 90 to 110 litres
    • 90L = 23.77 US gal / 19.80 UK gal
    • 110L = 29.05 US gal / 24.19 UK gal

Watts: 25W

25W
50W
75W
100W
200W
300W
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