OK, so I saw the video polzn bladz made about gethering rainwater. I noted the exact same TDS reader he was using. It was the HM digital TDS EZ. So I bought one myself. I'd been wanting to test the TDS of my water for a while. And I'm happy to say my Rochdale tap water is around about less than 50 PPM. This stuff all comes from upland reservoirs and I think it's safe to say it's pretty soft. Then I wanted to test what TDS it would be with detergent in. First I tested glass gleam 3 at 1:1000 dilution ratio, and it actually pushes it from 50 PPM up to around 60. Glass gleam 4 at 1:500, even though it has water softeners in, actually pushes the water up to around 70 PPM. Then I tested magnum washing up liquid. Now I can't be objective with how much I put in the water. I put "A squirt" in. And I wasn't really surprised to see it pushes it up to around 250 PPM. It's no wonder lines and direction marks are not an issue for me now that I'm not using washing up liquid anymore.