What Is the SLAM Process?
SLAM stands for Shock Level And Maintain. It is a controlled process for clearing algae and restoring water clarity by raising Free Chlorine, or FC, to a target based on the pool’s cyanuric acid level, then maintaining that target until the pool is clean.
SLAM is not one large chlorine dose. The chlorine is consumed as it attacks algae and other contaminants, so the pool must be tested and re-dosed repeatedly. The more often the target FC is restored, especially early in the process, the faster the cleanup usually goes.
What to Do During a SLAM
- Test FC frequently and restore it to the target level.
- Brush walls, steps, ladders, corners, and other low-circulation areas.
- Keep the filtration system running and clean or backwash the filter as pressure rises.
- Remove leaves and debris that continue consuming chlorine.
- Maintain proper circulation throughout the pool.
When Is the SLAM Finished?
The process is complete when the water is clear, combined chlorine is 0.5 ppm or lower, and the pool passes an overnight chlorine-loss test. Stopping as soon as the water looks better often allows algae to return.
Common SLAM Mistakes
- Treating SLAM as a one-time shock dose.
- Letting FC remain below the target for long periods.
- Using an unreliable CYA result.
- Ignoring brushing, filtration, and hidden algae areas.
- Attempting a very high SLAM target instead of lowering excessive CYA first.
Pool Gal Pro Tip 💦
The fastest SLAM is the one you maintain. Test and re-dose as often as practical at the beginning instead of letting the chlorine fall for hours.
The fastest SLAM is the one you maintain. Test and re-dose as often as practical at the beginning instead of letting the chlorine fall for hours.