thx purp. so i went to the petstore and got a ph tester and ph down liquid drops. my tap water tested out at over 7.2 ph- my chart only goes to 7.2, so it may be higher. however, i used drops per directions, and could not get the water to drop in ph at all! i had a fresh 5 gal bucket and tried for 2 hours using different strategies, but nothing would work. so finally i used powder stuff that came with SH system, and that lowered it to the 6.5 area. i put it into resevoir, added my 1/4 bag of micro and grow nutes , and re-tested it. it tested near to 6.5. i figured i had solved my ph problem. i then left the house for about 4 hours, and when i got back, i re-tested water and it was at or above 7.2 again! WTF ?? so i added powder stuff directly into resevoir, stirred it, and it tested it again. it tested fine. i dont understand what happened and why it keeps going back up... theres no way i can grow out of this system succesfully if i cant get the ph to hold at what i want....