Related Clues:

• Heartburn causes, maybe
• Etcher's etchers
• Lab bottles
• Rust removers
• Substances low on the 49-Across
• Pool supplies
• They're not basic things
• Omega-3s, e.g
• Some corrosives
• Bases' neutralizers
• Sour liquids
• One side of the pH scale
• Reactors to litmus
• Boric and amino
• Detectives go in because they're sour