ph water

i use soil for my garden,whats the ph supposed to be for watering them? iv recently bought sum more ph indicator n it says a different number to what the last one was,even if the ph indicator uses a different colour chart the numbers should be the same right?

The water should be 6.5

Make sure u look at those color charts under incandescent ltg..u'll get false readings under hps ..fo sure
And ur soil runoff should be around 6.5