dont you find it odd that 8 brands of soil all gave you the same reading with drops? thats pretty hard to believe. and im a little curious how it could possibly have lowered pure ph up to 4 or 5. that sounds like your drops have lost their potency or something. unless you ran a very small amount of ph up thru a very large amount of soil it should have still read very very high. hanna makes good meters but i wouldnt get a real cheap one it will only add to your headaches. i would also suggest getting rid of the vinegar. it is a pain in the ass, it doesnt stay stable and it has a ton of salt in it....