Hi Mani, no need to test the PH for potted compost, in the UK I buy John Innes no2 for small pots and John Innes no3 for large pots. I mix this with horticultural grit, fine horticultural bark and a little peat. You could say it's almost an Alpine mix tbh. Lots of air to circulate around the roots. Not rocket science, as I said in the other posting, 'recreate a maples natural habitat'.