"Martin" wrote in message ...
Does anybody have any comment on using a small proportion of tap water to
make up my tank, due to the size of containers I can get and the distance
to travel the initial set up of my tank would be easier if I could about
5- 10% tapwater.

Why not do initial set up with 10% of water missing at all
and add this missing 10% water later on. You do not care
that the tank is not filled to the top, do you ?
I would leave it not filled rather than fill it up with tap water.