I rolled back some loose lay vinyl flooring I had put down earlier this year and noticed some discoloring on the back, (black,brown,purple,marks) The vinyl is in a basement on concrete. The concrete feels waxy and while not wet appears to look damp in a few spots (its hard to explain) The basement had a leak at the start of the year I removed the old carpet and pad and then bleached the floor and ran a dehumidifier for about 2 weeks emptying out the water as needed. I did not check the moisture concrete before I put the vinyl down (big mistake) I am thinking of rolling the vinyl back up and checking the moisture levels. Is there anything else I should be doing ? should the concrete be sealed ? is there a good consumer grade moisture meter that someone could recommend ? What reading should I be getting off the concrete ?