I have no used vinegar so I can't speak on that. I use PH up and PH down from from general hydroponics. It very could well be chlorine and some other element that's in your tap. go to wal mart, buy a 5 gallon jug for $13 fill it up for 1.85 everytime after. 5 gallons for 1.85 isn't so bad especially when it's pure as can be. You will have great water to treat your plants and in time you can see if it's your tap. But since all 40 aren't like that, it's possible that it could not be your tap. Maybe, the vinegar, maybe not i've never used it.