What are the best aquarium heaters for saltwater tanks?

The Helio PTC Heater is a solid-state PTC titanium heating system with a dedicated controller, remote titanium probe, magnetic mounts, audible alarms and multiple safety fail-safes. It's designed for stable, corrosion-resistant heating in saltwater aquaria and is sold in single- and dual-element wattage configurations with a five-year warranty.

The Helio 200W is a PTC titanium heating element paired with the Helio Universal Controller, offering digital temperature readout, alarms, and dual-heater control for redundancy. It is fully submersible, corrosion-resistant, and intended for 25-50 gallon aquariums, suitable for reef and saltwater setups needing reliable, fast heating.

Electronic glass aquarium heater with a precision electronic thermostat (±0.4°C), ceramic heat sink, LED temperature display and One Touch control. Designed for freshwater and marine tanks up to about 230-300 L, it is fully tested and calibrated by AquaEl for reliable continuous operation. Suitable for disease treatment and steady temperature maintenance.

Slim, fully submersible electronic heater with shatterproof housing, LED display and ±0.5°F accuracy; monitors and self-adjusts power for efficiency and safety. Suited for small to medium freshwater and saltwater aquariums requiring precise temperature control.

The EHEIM Jager TruTemp 200W is a fully submersible rod-style aquarium heater with a shatter-proof laboratory glass jacket, TruTemp calibration dial and run-dry safety shut-off. It provides precise temperature control (±0.5 °C) across 18-34 °C and includes suction-cup mounting and an on/off indicator light, suitable for freshwater and saltwater aquaria.

The SICCE Scuba 200W Contactless heater is a submersible, app-adjustable aquarium heater using NFC contactless control via the SICCE ContrAll app, with dual dry-run protection and shatter-resistant high-density glass construction. It offers precise temperature control (15-35°C) and energy-saving mode, suited for medium aquariums. The unit includes strong suction cups and a 2.2 m cable.

External inline heater with a self-limiting PTC heating element, electronic temperature control and indicator light; available with 12 mm or 16 mm internal tube fittings and rated 200 W. Suited for use with canister filters or sumps and designed for vertical mounting and continuous safe operation.

Hydor ETH/Inline 300W is an external inline heater using PTC self-limiting technology designed for return lines from canister filters or sumps. It provides precise electronic thermostat control and is intended for marine and tropical aquaria where an external heater is preferred to keep equipment out of the display tank.

The Eheim Jager 300W is a fully submersible TruTemp heater with a laboratory-grade glass jacket, precise adjustable temperature from 18-34 °C and ±0.5 °C control accuracy, plus dry-run protection and an indicator light. It's a rod-style heater about 20 in long designed for even heat distribution and safe use in freshwater and saltwater tanks. It includes suction-cup mounting and a long power cord for flexible placement.