John,
Melbourne tap water is usually very soft. I don't know which reservoirs
are supplying your water but the TDS of the reservoirs for the south
east are usually in the 40-80ppm range. Check your water company's
website for their water quality tests. If you're at all concerned about
chlorine (which is generally low to start with), let the water stand
overnight and it will dissipate out.

John Varigos wrote:
Thanks Tennis for the feedback. Unfortunately Australia is in the grip of
the worst drought in our recorded history so no rain to speak of so will
have to go with tap water until the climate changes. But feedback from
other Melbourne growers indicates no problem using tap water.

Cheers
John

"tennis maynard" wrote
I do grow disas and have for about five years now. I can only tell you
what I have been told by others who have grown them longer and studied
them. They need as pure water as you can arrange. I have been told that
TDS must be kept below 200ppm (even with fertilizer in it), better yet,
below 100ppm, to successfully grow them. As my tap water tests out at
265ppm (nmysteriously, as the first year it tested at 412ppm), I use
rainwater which tests for me at 11ppm.