Sydney pH at 8.4!

[Squik]

Hi everyone,
Not new to goldfish, but new to this problem.
I've just started fishless-cycling a tank and tested for pH the day after starting the cycle ... 8.4!
Thought it may be the gravel, but it also tested 8.4 from the tap, the same after a day of aging. A massive change from the local water supply over the last eight years @ 7.5-7.
I've reserved a TV Ranchu for end of next month, but need to balance out to match the breeder's water - 7.2 to 7.6
Looking at either;
Seachem Neutral Regulator
Driftwood
Eheim Torf Pellets

Has anyone else had this issue recently? Really don't want to bounce the pH around too much, but am after a long term solution. Suggestions on which product is the safest?

Thanks in advance for your help

(custom 35x35x35cm cube with Fluval Nano Filter. Ammonia @ 4ppm, pH 8.4)

 

[Squik]

Update:
After reading some old threads it sounds like the Eheim Torf is what I need.
I'm confused how to balance it though during a weekly 50% water change, will it shock my fish or do I need to use some overnight in my changeover water first?
Never having used peat before, is pH drop decided by quantity used?

Thanks