Review on 🚰 J.C. Whitlam FLOW32 Flow-Aide System Descaler - 32oz (1qt), White by Carrie Robinson

I buy this item together with the pump and hoses to descale my water heater because it often stopped working (a day or two) and every time it stopped working , I have to reset. I used everything in the bottle and added some water, probably a gallon or two of water. After that, the water heater worked normally (at least for the last four days continuously). I then found a black greasy substance in the bucket, although many other reviewers complained about this, and the color of the metal part of the hose changed. . Don't know if it's harmful or not. I have a complaint about the product ie there is no clear guide on how to use it and how much to use.