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

https://fish-tank-capacity-calculatoruwqy881.evergrovio.com/posts/the-most-successful-fish-tank-liter-calculator-experts-have-been-doing-three-things

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