well filling new pool. treat to prevent?

[mbar]

The reason I said to take the chlorine up slowly is so that if there isn't enough sequstering agent in the water when you shock, the metal will fall out of solution and land on the surface of the pool. This was before you said you have cc - that's why it is good to always post the numbers. If you have a cc I would still add the chlorine slowly to get up to shock levels so that you can see if there is any stain forming. If you have a sand filter or DE filter you can add a chlorine puck to the skimmer while the pump is running. This will cause the water that hits the tablet to go right to the filter so that if the stain will fall out it will fall out on the filter medium first. The way that metals fall out of suspension is when the chlorine gets high, and the ph is high too. When dealing with metals it is a good idea to have your ph on the low side when shocking the pool. Also to have enough sequestering agent in the water to bind with the metals so that the high chlorine levels won't cause the metals to fall out of suspension. So my reasoning is until you know what your water will do, it is best to take it up to shock levels slowly - not all at once. When you get up to shock, and you have no stain, it means you have enough sequestering agent in to take care of the metals. Let me know if you have any other questions.

[induce]

excellent!!
thanks!