Review on Efficient hygger 300W 500W Aquarium Heater with External Digital Temperature Controller for 30-120 Gallon Tank - Ideal for Reef Saltwater Fish Tanks by Josh Payton

I have about 6 90 to 3 gallon aquariums. I have this heater for 5 out of 6 tanks. Love the fact that the controller is amazing and pretty much changes the temperature in seconds rather than set, wait, set, wait, you all know what I'm talking about, sometimes it's very difficult to control the temperature on heaters without an external to regulate controller. I wonder why these manufacturers don't control heaters with apps, we can with lights. js.