Ph is one of the most important issues about growing and getting right is a matter of survival for your plants. There is a chart in the FAQ section you should DL to your desk top. It will give you the Ph range of available nutrients for the plant. That way you match the Ph to the cycle of life the plant is in and the style of growing.

You are correct that some strains will want higher Ph then others but that is because of the available nutrients that they require not because of anything else.

The chart will help you more then posting questions every time.