Total Hardness (as CaCo3) 35g/m3
pH 7.7
Turbidity 0.15 NTU
Sodium 12 g/m3
Potassium 1.9 g/m3
Lead 0.002 g/m3
Arsenic 0.009 g/m3

Trichloromethane 5.4 mg/m3

As you can see my PH is high but I have no GH or KH 1dh
How do I get my PH down and hardness up
I am using DIY co2 in 60 liter tank
From what I have read I need caco3. How long does this take to dissolve into
the water
Will this take the ph up again?
Can I take my water replacement water down to ph6 and then use Baking soda
to get 4 hardness and a ph of about 7?

Its a very tricky balance and the more I read the more unbalanced I become!
Thanks