AquaHeat Pro adjustable heaters safely and reliably ensure the correct temperature in your aquarium. Certified by TUV/GS. AquaHeat Pro adjustable heaters safely and reliably ensure the correct temperature in your aquarium. Thanks to the use of high-quality silver contacts and a modern design, AquaHeat Pro adjustable heaters naturally meet the highest standards in terms of functionality and safety, and are certified by TUV/GS.