rain water or not?

[blake01]

hi guys, we have 2 poly water tanks 13500 litres each, we live out of town and have access to town water.
The tanks also have first flush diverters on them, our roof is colourbond.
The town water ph is 7.6, the kh is 9 and the gh is 179.
But the rain water is 6.5, the kh 2 and gh 35 (api test kits)..... sooooo do you think it would be safe to use 100% rainwater for discus fish? I havent started the cycling yet so im ages off even getting the discus.
Could i use a little crushed coral in the filter to help prevent a ph crash?

[ILLUSN]

mate that water would be perfect!

i'd just use 1 or 2 teaspoons of crushed coral if any,
get them onto that water and you'll have babies in no time :)

just a tip do daily 10% changes to lower the ph slowly down to 6.5 once you hit it your all set.

[blake01]

excellent!! thanks heaps for the reply
:D