Can I get help figuring out if the following is under the limit$?$

A company uses a chemical that has Zinc Chloride, which is a reportable chemical to their local regulators. The company has a local limit of $5$mg$/$L for Zinc Chloride. The chemical is a mixture of Zinc Chloride at $25-72\%$ and water $28-75\%.$ The company has an expected usage of $0\mathrm{.}5$ gpd of the chemical. Utilizing the highest expected value of Zinc Chloride $72\%,$ what would be the concentration of the chemical for their total flow of $50,000$ gpd$?$