Other known temperature controllers with less than 1 degree of precision?

One potential alternative to the Apex unit for temperature control with less than 1-degree precision is the Inkbird ITC-306T. This controller can provide precise temperature measurements and regulation for various applications, including aquariums. The Inkbird ITC-306T supports dual relay output and has an accuracy of ±0.1°C, making it a reliable option for maintaining stable environmental conditions. However, it is important to consider that this controller is primarily designed for general use and may require additional steps, such as encasing the probe in a protective housing, to ensure it functions optimally in a saltwater tank environment.

Another viable option worth considering is the Ranco ETC series, specifically the Ranco ETC-111000. This digital temperature controller offers a high degree of accuracy and flexibility with user-defined settings that can be finely tuned to achieve the desired precision. The Ranco ETC-111000 is widely used in various industrial and commercial applications, ensuring its reliability and durability. Similar to other general-use controllers, measures should be taken to protect the probe from the corrosive nature of saltwater to maintain accuracy and prolong the lifespan of the device.