My bathroom was recently remodeled and I had a Jacuzzi put in. I used Delta fixtures for the tub/shower and the sink. The plumbers used red and blue Pex lines connected to my copper pipes. When I turn the tub on for the first time each day, the water comes out red for about a second. The sink is unaffected. I use city water, not well and I have never had this problem. We have let the water run several minutes each day, but when we turn the water in the tub on the next morning (or several hours later) the red water still comes out for a second or two. The bathroom has been completed for about one and a half weeks. Can you tell me what is going on?