TDS rising?

[HarleyC]

Thanks.
The cartridge is fairly new and it reads zero straight out bin initially.
I tend to think the bin leaching may be the culprit too, as when I did my first TDS reading in there it was showing over 50ppm.
I gave a good rinse and it shows zero initially, but then after a day or two it shows 10.
May try different bin.
My meter is a hand held one you dip in water - If someone is in the market for one, I got it free with my household Zero water filter - Like a Brita only better.