After the Equilibrium added the tank water is around 5dgh General Hardness and the Kh is around 1.5. Out of the tap the GH is very low, barely measurable with the test kits. Total TDS out of the tap is a around 17ppm, thus why I need to increase the hardness using Equilibrium. After a week of use the Purigen it is quite dark, probably will need to recharge in another week, still pretty impressed with the stuff. I am sure over time and the fact I have increased the hardness that tannins should level off and not be that much of a issue.