check out this placehttp://www.eseasongear.com/ i got the hm tds-4, it seems to work fine.I can't see vinegar being a problem, a lot of guides say to use it to lower ph and they don't mention anything about it damaging plants. Can't speak from personal experience yet though. btw, where did you get your ph meter from? I'm looking for one myself
its been about five hours now and still at 6.6...
so i guess i will tell you 2mora sum point if its changed any..
thanks again all