My Tap Water Test Results.

No that isn't high for tap water Thor.
Water companies I believe are allowed up to 50pmm. Mine, I think is about 15

Unless you are desperate to have fish that demand softer and more acidic water, you should be fine at pH 7.6. Fiddling around trying to change pH often does more harm than good and doesn't always work anyway.

It would also help to know your hardness. While you can buy tests for that, it should be on your water company's website. If you find it, make a note of the unit they use as well as the number. Water companies tend to use different units from fish keeping websites so it will need converting.

If that value of 266ppm is ppm CaCO₃, that is actually hard rather than medium hard.

The bands I've found are:
150 - 200, medium hard
200 - 300, hard
300+, very hard

Every site or book you look at has different band boundaries.
I used Northumbrian Water's boundaries (my water company) which are, in mg/l Ca:
40 - 60 = slightly hard
60 - 80 = moderately hard
80 - 120 = hard
120+ = very hard

I converted those to ppm CaCO₃ in my last post (the conversion factor is multiply mg/l Ca by 2.5 to get ppm CaCO₃)