filtered "top-up" water?

[fishdude]

Good day

I'm curious to know what peoples feelings are on filtering Calgary water
before use in their aquariums.

I'm presently using a reverse osmosis for my 120 gal reef and tapwater(de-chlorinated) for my 260 gal fish only. All inhabitants seem to be happy in both tanks.

A few years ago I asked Calgary waterworks to send me a breakdown of
our drinking water . They will email this free of charge and test the water for about 40-50 items twice daily. There are even measurable amounts of gasoline!!??

How have you folks been pre-treating your water?

cheers

FD