ph help?

im using a cheap combined moisture/light/ph tester with metal probes. i stuck it in the soil and reads roughly between 7 and 8 its not digital!! as the tester only goes up to 8 it looks like it hardly moves. is this ok for the soil? and also can i test my water with this? cuz i put it in the water and its same as soil but im not sure if these things give accurate reading? can i add vinager to water to bring it down with no harm? thanks

Would be helpful if you provided more info like product name and product info.

I would not use vinegar to lower the ph you need to add acidity ... Lowering soil pH=acidification..Peat would probably be the easiest additive to add the acid as it breaks down. Past that, I'd probably head out to any big box store or garden center and pick up a bit of Hollytone (fertilizer), MirAcid (fertilixer), Aluminum Sulphate or Dusting Sulphur (both additives). 7ph is great past that would be to high if it is 8 then you need to lower it.