Review on Soyon Submersible Aquarium Heater - Adjustable Temperature 100W, 200W, 300W, 500W - Ideal for Fish Tanks 10 Gallon to 100 Gallon - Efficient Water Heater by Rob Dixon

I am new to tropical fish keeping. I have a 10 gram tank which I originally bought a very basic 50 watt heater for and which couldn't handle 78 degrees Fahrenheit, especially since the weather is getting cold here in New York. My rooster just died from an illness and I'm not sure if it's temperature related. I think I should buy a more powerful heater before winter comes and all my fish die, so I bought a 100 watt heater. It's only been in my tank for a day but I like it compared to my old one. Installation was easy but the only thing is a bit long for my 10g tank. He says you should keep it upright and fully submerged. I have water that comes up to the rim of my tank and covers most of the heater except for the top part which is the plastic part of the controller. I hope everything is fine. So far it has done a great job of keeping the water at 78F. It's around 50 to 60 degrees here so I set it to 80 degrees to make up for the cold weather and the water temp is ideal at 78F. The fact that it has temperature control makes it very appealing to me. My last one didn't have that, so I really appreciate it.