I do like @Archerfish . I age my water in a 44 gallon container and put my big 150 watt Eheim in it a day before. Something I heard once is that slime and disease stuff grows in hot water heaters and the person I heard this from never cooks in hot water from the tap , instead drawing cold water and heating it up on the stove. I tend to believe this. The hot water heater never gets cleaned out and nobody runs enough hot water to flush it regularly and the water does not boil or get hot enough to kill bad organisms. Think what you want about that but I prefer to err on the side of caution.