Inline heater for water changes?

[Phoenixfishroom]

Is it possible to use a high powered inline heater like 500 watts maybe to heat the tap water to temp on demand for water changes? Or has anyone tried one of those mini tankless water heaters that go under the sink that you can get for like 80$?
I simply do not have access to enough hot water to do all of the water changes even if I spread them out. And now adding a 150 gallon, 100 gallon, and another 60 breeder for large breeding projects… I need to figure out hot water on demand without breaking the bank

[Phoenixfishroom]

My biggest single water change is like 50 gallons at a time but that’s just one tank… we are talking hundreds of gallons at a time potentially

Actually run out of water and have to boil water to do the smaller tanks after running out the hot water heater to do the bigger ones

I have over 20 tanks, 7 of them are 60+ gallons, there is a 150, 100, two 75, three 60s