pH Problem

I measured the pH of my tap water yesterday and the pH was 7.3, so I left it out. When I checked it today it was 8.3! Does it usually go up when left out?

You need to get some ph up and down man! Hard water goes up and down a lot, I constantly check mine once or twice a day at least.

i have heard that the salts in tap water will do that if can collect rain water or if out in country look for small stream or spring or river because they are fed by springs, rain or melting snow or ice just check water ppm before useing it to make sure if plants and fish live in it ilbe safe to use but dont have nothing close by i know wall mart carrys a flter and pither that claims to take the ppms to 0 and also comes with a ppm meter

try bubbling your tap water with a fish tank air pump, within a day or two it should come down. if not you may want to consider RO or distilled water, or ph down. the air pump will come in handy too if you start to make you own microbial tea in the future, which i also suggest. if you do go the bottled route make sure your nutes have adequate calcium and magnesium, if not you'll need a cal/mag supplement. some tap water is super high in heavy metals, and not the Pantera kind. so ph down might only mask a bigger issue with the water.