Got my di & 2 weeks ago tried with no success to make pure water. Didn't work so chucked di in she'd. After having a few words with our member of the month & trying a few things he said today I tried again with success. My ppm was fluctuating between o & 4 so got an average of 2 which compared to last weeks 140 is great. Having read that most of you use it ok up to 5 I was dead happy with that & as I only use it every now & then on hard to get windows I am a happy bunny (& so's my misses as made no mess this time). Connecting my other di to it should give me 0 all the time but at mo just happy with what I got. So a big thank you to Mark & you others that gave me advise.