Guide
SLAM Method Explained — Clearing Algae the TFP Way
What the SLAM method is, how FC targets relate to CYA, and how to track overnight FC loss until the pool is clear.
SLAM stands for Shock, Level, And Maintain — a Trouble Free Pool (TFP) style protocol for clearing algae by holding high free chlorine (FC) until overnight loss is small and the water is clear. Pooldex is not affiliated with Trouble Free Pool; this guide paraphrases the idea for searchers who land here first.
The idea in one paragraph
Measure CYA, set an elevated FC target based on that CYA, keep FC at that level (usually with liquid chlorine), brush, filter continuously, and retest often. When the pool is crystal clear and overnight FC loss is ≤ ~1 ppm (rule of thumb), you’re done — then maintain normal FC for your CYA.
Why “shock once” often fails
A single bag of shock can raise FC for a few hours. Algae and organics chew through it. If you walk away, FC crashes overnight and the green comes back. SLAM is about sustained FC, not one heroic dose.
What you’ll do day to day
- Test FC (and CC if you track combined chlorine) frequently during the day.
- Dose chlorine back up to the SLAM FC target when it drops.
- Brush walls and floor so chlorine reaches the algae.
- Keep filtration running; clean/backwash as needed so water actually moves.
- Watch overnight FC loss as your exit criterion — not “it looks better.”
Safety
- High FC is harsh on skin, hair, and swimsuits — keep people out as appropriate.
- Never mix chemicals. Follow labels.
- Store chlorine properly; don’t invent chemistry in a closed room.
SLAM vs “pool shock”
People search “shock the pool” when they mean anything from a light FC bump to a full algae fight. See pool shock vs SLAM for the naming trap.
Track it in Pooldex
SLAM is a log-heavy process. Pooldex includes a SLAM assistant so you can see targets, log doses, and watch whether FC is actually holding — without an account, and without uploading your readings to us.