reduce pH? help

I tested the tap water i am using to water my plants and it reads around 7.6 This is too high and people have told me that it is locking our Nitrogen. Therefore i need to reduce the pH of my tap water.

My pH tester is for my aquarium and only tests as low as 7.4. So I am wondering if anyone whos good in chemistry good get me the quantities of baking soda or vinegar i would add to 1 litre of water per say.

Thanks a lot

The amount you need will depend on the parts per million (ppm) in your water. It varies from city to city. You really need to get a ph meter. you can get one here for $20. Free shipping.
www.eseasongear.com

cider vinegar.

If not at least try to get a different kit. One for pools maybe. Wall mart should have one.
GL to you.