So our water heater was on its last leg and needed to be replaced. Today after the new heater was installed I noticed the water smelled like that "new" smell. When I do water changes on my tanks I use alittle hot water to make sure the new water is about the same temp as the tank water. My question is, is it safe to use my hot water? I smell it and I am worried that it might harm my fish. If I have to wait how long till I can do water changes? Thanks!