1. Consignes de sécurité importantes
Veuillez lire et comprendre toutes les consignes de sécurité avant d'utiliser cet appareil. Le non-respect de ces consignes peut entraîner un choc électrique, un incendie ou des blessures graves.
- Always disconnect the heater from the power supply before performing any maintenance, cleaning, or handling inside the aquarium.
- Ensure the heater is fully submerged in water before connecting it to the power supply. Never operate the heater dry.
- The heater is designed for indoor use only, specifically for aquariums. Do not use it for any other purpose.
- Inspect the heater and its power cord regularly for any signs of damage. Do not use if damaged.
- Tenir hors de portée des enfants.
- The heater features an additional safety shut-off to prevent overheating.
- The borosilicate glass tube is heat-resistant and shock-resistant, but handle with care to avoid breakage.
2. Produit terminéview
The Tetra HT 25 Electronic Aquarium Heater is designed to maintain a stable and optimal water temperature for tropical fish in aquariums ranging from 10 to 25 liters. Its fully electronic design ensures high precision and reliability.

Image 1: Tetra HT 25 Electronic Heater. This image displays the packaging for the Tetra HT 25 Electronic Heater. The packaging highlights the product name 'HT 25 Electronic Heater' and the brand 'Tetra'. It also shows the heater unit itself, which is black with green accents, and indicates features such as suitability for 'up to 25L' aquariums, 'plug and play' operation, and 'safety tested' certification. The heater is designed for 'fish well-being' by maintaining 'optimal temperature'.
Caractéristiques principales :
- Electronic Precision: Fully electronic with an integrated microprocessor for accurate temperature control.
- Température réglable : Temperature adjustment knob allows setting between 20°C and 32°C in 1°C increments.
- LED d'état: 3-stage status LED for easy monitoring of the heating phase.
- Construction durable : Extra thick, heat-resistant, and shock-resistant borosilicate glass tube.
- Caractéristiques de sécurité : Waterproof cap, fully immersible design, and additional safety shut-off.
- Installation facile : Secure attachment with two suction cups and a 1.6 m long power cord.
- Aquarium Size: Suitable for aquariums from 10 to 25 liters.
3. Configuration et installation
Follow these steps to correctly install your Tetra HT 25 Electronic Aquarium Heater:
- Déballer: Carefully remove the heater from its packaging and inspect it for any damage.
- Placement: Choose a location in your aquarium where water circulation is good. This ensures even heat distribution. Avoid placing it directly in the substrate.
- Attachement sécurisé : Use the two provided suction cups to securely attach the heater to the inside wall of your aquarium. Ensure it is fully submerged and positioned vertically or at a slight angle.
- Réglage de la température : Before plugging in, use the temperature adjustment knob at the top of the heater to set your desired water temperature (between 20°C and 32°C). For most tropical fish, a temperature between 24°C and 26°C is ideal.
- Connexion électrique : Once the heater is fully submerged and the temperature is set, connect the power cord to a suitable electrical outlet.
- Surveillance initiale : Monitor the aquarium temperature with a separate thermometer for the first 24 hours to ensure the heater is maintaining the desired temperature accurately. Adjust if necessary.
Important: Ensure the heater is always fully submerged when powered on. Operating it dry will cause damage and void the warranty.
4. Fonctionnement
The Tetra HT 25 heater operates automatically once plugged in and submerged. The integrated microprocessor continuously monitors and adjusts the heating element to maintain the set temperature.
- Réglage de la température : To change the temperature, unplug the heater, adjust the knob to the new desired setting, and then plug it back in. Allow time for the aquarium water to stabilize at the new temperature.
- LED d'état: Les 3-stage status LED provides visual feedback on the heater's operation:
- Conduit sur: The heater is actively heating the water.
- DEL éteinte : The water has reached the set temperature, and the heater is in standby mode.
- LED clignotante : Indicates a potential issue or safety shut-off activation. Refer to the Troubleshooting section.
- Interruption d'alimentation: En cas de coupure de couranttage, the heater will resume normal operation once power is restored, maintaining the last set temperature.
5. Entretien et nettoyage
Un entretien régulier garantit la longévité et le bon fonctionnement de votre appareil de chauffage.
- Débrancher l'alimentation : Always unplug the heater from the power outlet before removing it from the aquarium or performing any cleaning.
- Refroidir: Allow the heater to cool down for at least 15-20 minutes after unplugging before removing it from the water. This prevents thermal shock to the glass.
- Nettoyage: Gently wipe the heater's glass tube with a soft cloth or sponge to remove algae or mineral deposits. Do not use abrasive cleaners or harsh chemicals.
- Ventouses : Periodically check the suction cups for wear and tear. Replace them if they lose their grip to ensure the heater remains securely attached.
- Stockage: If storing the heater, ensure it is clean, dry, and stored in a safe place away from extreme temperatures.
6. Dépannage
If you encounter issues with your Tetra HT 25 heater, refer to the following common problems and solutions:
| Problème | Cause possible | Solution |
|---|---|---|
| Heater not turning on (LED off) | No power; heater already at set temperature. | Check power connection. Verify aquarium temperature with a separate thermometer. If temperature is below set point, check power outlet. |
| Aquarium water not heating up | Heater too small for aquarium volume; incorrect temperature setting; poor water circulation. | Ensure heater matches aquarium size (10-25L). Increase temperature setting. Improve water circulation (e.g., with a filter). |
| Heater LED flashing | Safety shut-off activated (e.g., heater operated dry or overheating). | Immediately unplug the heater. Allow it to cool down completely. Ensure it is fully submerged before plugging it back in. If flashing persists, the unit may be faulty. |
| Temperature fluctuates significantly | Poor water circulation; external temperature changes. | Ensure good water flow around the heater. Minimize drafts or sudden temperature changes in the room. |
If the problem persists after trying these solutions, please contact Tetra customer support.
7. Spécifications
- Modèle: Tetra HT 25
- Pouvoir: 25 W
- Volume de l'aquarium : 10 - 25 litres
- Plage de température : 20°C - 32°C (réglable par incréments de 1°C)
- Dimensions: Approximately 5 x 9 x 28 cm (Product Dimensions: 5 x 9 x 28 cm; 210 g)
- Longueur du câble : 1.6 m
- Numéro de modèle de l'article : 307049
- Matériel: Borosilicate glass tube, plastic cap
- Utilisations spécifiques : Indoor aquarium heating
8. Garantie et assistance
The Tetra HT 25 Electronic Aquarium Heater comes with a Garantie de 2 ans À compter de la date d'achat, cette garantie couvre les défauts de fabrication dans des conditions normales d'utilisation.
La garantie ne couvre pas les dommages résultant de :
- Mauvaise installation ou utilisation.
- Operating the heater dry (not fully submerged).
- Accidental breakage or misuse.
- Réparations ou modifications non autorisées.
For warranty claims, technical support, or further assistance, please contact Tetra customer service through their official website or the retailer where the product was purchased. Please have your proof of purchase and the product model number (HT 25, Model 307049) available.





