The steps on our inground pool are very yellow. We took in a pool water sample and it came back with high levels of copper. After using the chemicals they sold us to chelate the metals in the pool, we took in another water sample and the metals were in normal range. We shocked the pool and low and behold the yellow returned within hours. We took another water sample in and was told the metals were high again and we needed to repeat the process. I'm not sure how that could happen after just shocking the pool. We contacted another pool company who sold us a different chemical to remove the metals and he also told us to empty half the water out and replace it to dilute out any remaining metals. We did both. Our pool was cloudy and since we live in Texas and it has been in the 90s we shocked the pool. Well we have yellow steps again. Everything else was in range. What is causing this and how do we fix it? It has cost us quite a bit already. BTW when we use ascorbic or citric acid it clears the steps up but eventually the yellow comes back.