With an aquarium calculator, you can approximate heater size and temperature targets

https://aquarium-weight-calculatorsefq631.urbanvellum.com/posts/12-facts-about-aquarium-gallon-size-calculator-to-make-you-think-about-the-other-people

With an aquarium calculator, you can approximate heating unit size and temperature targets. Make much safer options for tropical, cold-water, or planted tanks.