ph question

my ph is low how do i bring it up ive been reading that fine dolomite lime will make it 7.0. and ive here that there's ph up and ph down, what is it, some type of liquid and is it safe for pot

this is what I use, it works great. I recommend you go get it at your local hydro shop since you can get it ASAP but I paid the same price as this.

http://cgi.ebay.com/Complete-pH-Control-Kit-System-General-Hydroponics_W0QQitemZ270350185140QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item3ef22072b4&_trksid=p3286.c0.m14&_trkparms=65%3A12%7C66%3A2%7C39%3A1%7C72%3A1205%7C240%3A1318%7C301%3A1%7C293%3A1%7C294%3A50

thank you for the info. jackherer