SO. I have a 125g tank.. I have 5 heaters in it.. YES, FIVE HEATERS.. 3 300watt Aqueon Heaters, and 2 250watt Stealth Pro Heaters. Why so many? because I originally started with the two 250watt heaters.. but not much heat. So my dad thought, why not buy another heater? maybe we dont have enough power in there? so he bought a 300watt Aqueon heater. eventually we had another in there and just yesterday we got our third aqueon heater in there.. so thats a total of 5 heaters. now i am SURE that most of those heaters are unneeded.. But the problem is we cant get the heat up past ~73 degrees. Even when all the heaters are turned up to the MAX which on the heaters is around 88 i think.. Now you know when you look at a heater underwater? and you can see it sort of distorting the way the water looks directly around the heater? well only ONE of them is doing that, so i think only one is working.. and its not even one of the new ones. its one of the old stealth heaters.. idk if this means only one of my heaters is working but ya... what should i do?