Recently a potential customer, from a distance away, sent me a water sample to test. He mentioned that they had color in their families water and was curious as to how I suggested it could be fixed. I did the usual tests but also put the water through my demonstration Tannin Filter so he could see the result and video taped it for him and you to see. More information here on our WS Tannin Filter 1.0 Cube WDTFPTN1