I see that Lowe’s carries this stuff. It claims to be 100% sodium hydroxide or lye. Has anyone used this?
https://m.lowes.com/pd/Roebic-Laboratories-Inc-32-oz-Drain-Cleaner-Crystals/4751600
https://m.lowes.com/pd/Roebic-Laboratories-Inc-32-oz-Drain-Cleaner-Crystals/4751600