Q: One of my wells has sand in the water. We have to replace impellers every few years because of the poor performance and loss of efficiency. Do you have any recommendations? A: If you are not already doing so, you may want to ask you pump contractor about using Ni-Resist impellers in place of bronze impellers. You will initially lose 1-2 efficiency points, but you will maintain a relatively higher efficiency over the life of the impeller. The impeller will also have a longer useful life.