FREESEA Aquarium Heater FS01 (25W, 1-5 Gallon) Instruction Manual

Introduction

Thank you for choosing the FREESEA Aquarium Heater FS01. This heater is designed to maintain a stable water temperature of 78°F (±2°F) in small aquariums ranging from 1 to 5 gallons. Its compact design, durable construction, and safety features ensure a healthy and stable environment for your aquatic pets. Please read this manual thoroughly before installation and operation to ensure proper use and longevity of the product.

Safety Information

Electrical Safety: Ensure the supply voltage matches the product specifications to prevent damage or accidents. Always unplug the heater before performing any maintenance or cleaning.
Submersion: This heater is designed for indoor aquariums only and must be fully submerged in water during operation. Never operate the heater in air or above the water line.
Cooling Period: Before removing the heater from the tank or cleaning it, always unplug the power cord and allow the heater to cool in the water for at least 30 minutes. This prevents thermal shock and potential damage to the heater or injury.
Physical Protection: The heater features an explosion-proof quartz glass core and a smooth PC cover to prevent cracking and protect fish from direct contact with the heating element.
Automatic Shut-off: The top sensor automatically shuts off the heater if it is approximately 2 inches out of water, preventing overheating or dry burn risks.

Image showing four safety precautions for the FREESEA Aquarium Heater, including ensuring correct voltage, full submersion, cooling before removal, and cleaning with soft materials. — **Figure 1:** Important safety precautions and maintenance guidelines for the aquarium heater.

Package Contents

Verify that all items are present in the package:

1 x FREESEA Aquarium Heater (FS01, 25W)
2 x Suction Cups
2 x Thermometer Stickers
1 x User Manual (this document)

Image showing the contents of the FREESEA Aquarium Heater package, including the heater, power cord, two suction cups, two thermometer stickers, and a user manual. — **Figure 2:** Contents included in the product package.

Setup

Unpack: Carefully remove all components from the packaging.
Attach Suction Cups: Securely attach the two provided suction cups to the heater body.
Position Heater: Place the heater fully submerged in your aquarium. Ensure it is positioned vertically or horizontally in an area with good water circulation. The heater must be at least 2 inches below the water surface.
Apply Thermometer: Attach one of the thermometer stickers to the outside of your aquarium glass, away from direct sunlight and the heater itself, for reference.
Connect Power: Once the heater is fully submerged and positioned, plug the UL certified 4.9ft power cord into a suitable electrical outlet.

Image showing the FREESEA Aquarium Heater being held next to a small 1-5 gallon fish tank, illustrating its compact size and suitability for small aquariums. — **Figure 3:** The compact heater is suitable for small tanks.

Image showing the FREESEA Aquarium Heater placed horizontally in a turtle tank with a low water level, indicating its compatibility with minimum 2-inch water levels. — **Figure 4:** Heater compatibility with low water levels, suitable for turtle tanks.

Diagram showing the internal components of the FREESEA Aquarium Heater, including the heat-resistant PC protect shell, nickel-chromium heating wire, non-corrosive quartz glass, MgO filling, and strong suction cup. It also illustrates the red light for heating in progress and green light for constant 78°F. — **Figure 5:** Heater components and indicator light functions.

Operating Instructions

The FREESEA Aquarium Heater is designed for automatic operation once plugged in and fully submerged. It maintains a constant temperature of 78°F (±2°F).

Heating Indicator: When the heater is actively heating the water, a red light will illuminate.
Temperature Reached: Once the water temperature reaches 78°F, the indicator light will turn green, signifying that the desired temperature is maintained. The heater will cycle on and off as needed to keep the temperature stable.
Out-of-Water Protection: If the water level drops and the heater is exposed by approximately 2 inches, the heater will automatically shut off, and an orange flashing light will alert you to a malfunction or low water condition.

Graph illustrating the constant temperature function of the FREESEA Aquarium Heater, showing the water temperature rising from 60°F to 78°F, then maintaining 78°F with minor fluctuations. — **Figure 6:** Temperature regulation cycle of the heater.

Image showing a person lifting the heater out of the water, demonstrating the auto power off feature when the heater is 2 inches out of water. Contrasting images show heaters without this protection leading to overheating or fish death. — **Figure 7:** Automatic shut-off feature for out-of-water conditions.

Image showing the FREESEA Aquarium Heater in both a freshwater tank and a saltwater tank, indicating its suitability for various aquatic environments and its ability to eliminate temperature fluctuations. — **Figure 8:** Heater application in freshwater and saltwater tanks.

Official Product Video: FREESEA Constant Temperature Aquarium Heater

This video demonstrates the FREESEA constant temperature aquarium heater in operation, showcasing its features and how it maintains a stable temperature in an aquarium.

Maintenance

Cleaning: Only clean the heater with soft materials. Avoid using hard objects or abrasive cleaners, which can scratch or damage the heater's surface or internal components.
Pre-Cleaning Cool Down: Always unplug the heater and allow it to cool in the water for at least 30 minutes before attempting to remove it for cleaning.
Regular Inspection: Periodically inspect the heater and its power cord for any signs of damage, such as cracks, frayed wires, or unusual wear. If any damage is observed, discontinue use immediately and contact customer support.

Image showing the FREESEA Aquarium Heater submerged in water, with insets highlighting its explosion-proof quartz glass and magnesium oxide (MgO) filling for even and safe heating. — **Figure 9:** Heater construction for even and safe heating.

Troubleshooting

Problem	Possible Cause	Solution
Heater not turning on (no red/green light)	Not plugged in; power outage; faulty outlet; heater not fully submerged.	Check power connection. Verify power to the outlet. Ensure heater is fully submerged.
Water temperature is too low	Heater not functioning; tank size exceeds recommended capacity; extreme ambient temperature.	Ensure heater is plugged in and indicator light is red. Confirm tank size is 1-5 gallons. Allow more time for heating in cold environments.
Orange flashing light	Heater is out of water or water level is too low.	Immediately unplug the heater. Check and restore the water level in the tank. Allow heater to cool before re-submerging and plugging back in.
Heater appears damaged (cracks, frayed cord)	Physical impact; wear and tear.	Do not use. Unplug immediately and contact customer support for replacement.

Specifications

Feature	Detail
Model Number	FS01
Power	25W
Recommended Tank Size	1-5 Gallons
Preset Temperature	78°F (±2°F)
Material	Explosion-proof Quartz Glass, PC Cover, Magnesium Oxide (MgO) filling
Dimensions (Heater Body)	Approx. 6.5 inches (length) x 1.18 inches (diameter)
Power Cord Length	4.9 ft (UL certified)
Safety Features	Auto shut-off when 2 inches out of water, shatterproof design
Color	Black
Item Weight	1.44 ounces

Warranty and Support

FREESEA provides a 1-year warranty for this product, covering manufacturing defects and malfunctions under normal use. Your satisfaction and the ecological stability of your fish tank are our primary goals.

For warranty claims, technical assistance, or any questions regarding your FREESEA Aquarium Heater, please contact our customer support team. Refer to the product packaging or the FREESEA official website for the most current contact information.

Manufacturer: FREESEA

FREESEA FS01