Big Water Change

[OldMan47]

I am going to suggest that you think about your plumbing before jumping to any conclusions about using hot tap water. In the US, almost all water heaters are fiberglass lined and are safe to use for filling a tank. In other places, other methods are used to heat water. If your water heating system places the water in direct contact with metals for any significant time, it may be best not to use the heated water. Some systems seem to contain vessels made of copper, if I am correctly interpreting what our UK friends are saying. I would avoid using hot water from a system such as that. The point is simple really. You can use any heating method that does not add anything in the form of chemicals or metals to the raw water.

 

[raptorrex]

I am going to suggest that you think about your plumbing before jumping to any conclusions about using hot tap water. In the US, almost all water heaters are fiberglass lined and are safe to use for filling a tank. In other places, other methods are used to heat water. If your water heating system places the water in direct contact with metals for any significant time, it may be best not to use the heated water. Some systems seem to contain vessels made of copper, if I am correctly interpreting what our UK friends are saying. I would avoid using hot water from a system such as that. The point is simple really. You can use any heating method that does not add anything in the form of chemicals or metals to the raw water.

contact with metals is irrelevant. use of a decent water conditioner/de-chlorinator ensures metals are bound.
in the UK, fiberglass is on the outside, of the hot water tank, not the inside. but as the UK use copper, there is no need to line. also glass lined tanks have strips of reactive metal,(magnesium/aluminium, so you have these metals being introduced to the system) well more reactive than the steel, so as to protect protruding steal fixings. the reason for glass lining is safety, but only because the tanks are made of a, comparatively, dangerous metal (steel).

i do understand how dangerous copper can be, in an aquarium, but the first line of the post, cover's that. ultimatly the water from the hot tap, in the UK, has to be "human safe". together with our standard precautions, thats enough to keep our fish safe. remembering the anti bacterial properties of copper (why you think they use it? lol), there is even chance water heated and carried in copper, is safer than water carried in other materials.