Is there a chemical that can be added to well water when filling pool for the first time keep from turning rusty brown?

To prevent the pool from turning rusty brown when filled with well water, sequestering agents like Calgon, sodium hexametaphosphate, and sodium tripolyphosphate can be used. These agents bind the metal ions and keep them from precipitating out as rust. Another option is to use ion exchange resins, which can remove metal ions from the water and can be regenerated for long-term use. Additionally, pH balancers and chlorine or bromine can be used to further prevent the water from turning rusty brown and maintain the pool's overall health.