Review on Hydor Submersible Glass Aquarium Heater Fish & Aquatic Pets in Aquarium Heaters & Chillers by Jose Gerber

Great product; After all these years it looks like I've finally found a heater that will keep my large aquarium warm without having to make adjustments every time the temperature changes. Also, it is strong enough to keep the water warm. As for us folks who need a little help, I would give the product ad a one star rating. *** On this page and other pages, you list the different powers that are available, with no help in choosing the power. After spending over an hour researching other websites that sold heaters, I concluded that my 50 gallon tank needed a 200w heater. Based on my research, I now understand why I had trouble buying underpowered heaters for years. Please help us to determine the correct heating capacity according to the tank size.