It worked like a charm. Within 15–20 minutes of pouring the granules down the drain followed by hot water, the blockage completely cleared. The water drained faster than it had in months. It’s cheap, readily available at hardware stores, and far more effective than most over-the-counter liquid drain cleaners.
This stuff is no joke. It generates intense heat and releases fumes when mixed with water. I wore heavy rubber gloves, goggles, and an old long-sleeve shirt, and I made sure the room was ventilated. You absolutely cannot use it if there’s standing water (it can boil and splash back), and it will damage aluminum, some plastics, and old pipes if left too long. Also, never combine it with another cleaner—especially anything acidic—or you risk a violent reaction. cleaning drain with caustic soda
Always add the granules to water, not water to granules, to avoid a violent eruption. And run cold water for a few minutes after the drain clears to flush everything safely. It worked like a charm