Landscaping - concrete edger block stain prevention

I am going to be putting down some concrete edger blocks, the common scalloped white ones. I have used them before, and since I water the scrubs with well water, I get the orange colored stain from the iron in the well water, which makes them look terrible in a short period of time. Once they are stained, they are done. No soap, or pressure washing is going to get them back to white.

Is there an effective clear seal for these stones? I mean something that will stand up to being exposed to the elements?

you are probably looking for some type of acrylic, but nothing I can think of is UV resistant. Perhaps a concrete sealer might do the trick but I do not know much about those.