Green Pool Recovery: Your Day-by-Day SLAM Plan
Calculate your shock level, log every test, and know exactly when you're done.
Updated · Reviewed by the Skimmer editorial team
SLAM shock calculator
Pick your shade of green
- Time to clear
- 2 to 4 days
- Chlorine to buy
- About 2 to 3x the first dose
- Vacuum to waste first?
- No, brush twice a day
Day-by-day SLAM log
Print this page and fill it in at the pool. Test at least morning, midday and dusk.
| Day | Time | FC | pH | Filter psi | Clarity (1 to 5) | Dose added |
|---|---|---|---|---|---|---|
| 0 | ||||||
| 0 | ||||||
| 0 | ||||||
| 1 | ||||||
| 1 | ||||||
| 1 | ||||||
| 2 | ||||||
| 2 | ||||||
| 2 | ||||||
| 3 | ||||||
| 3 | ||||||
| 3 |
Logging on paper? Skimmer charts your FC loss between tests so you can see when the overnight loss test passes.
The plan
- 1Day 0: Test CYA and pH. Lower pH to about 7.2 so chlorine works harder. Brush everything.
- 2Day 0: Raise free chlorine to your SLAM level (40% of CYA) and hold it.
- 3Run the filter 24/7. Clean or backwash when pressure rises 8 to 10 psi.
- 4Test at least 3 times a day and top FC back up to target every time it drops.
- 5Days 1 to 3: Keep brushing; the water goes green, then blue-cloudy, then clear.
- 6Confirm done with all three checks below.
- 7Let FC fall back to normal for your CYA and resume your routine.
Am I done? All three must pass
- The water is clear: you can see the main drain
- Combined chlorine is 0.5 ppm or less
- Overnight chlorine loss test: FC drops 1 ppm or less from dusk to dawn
Note: Overnight chlorine loss test (OCLT): test FC after sunset, test again before sunrise. With no sun, any drop over 1 ppm means something (usually algae) is still eating chlorine.
Still green after shocking?
| Cause | Fix |
|---|---|
| FC dropped between doses | Test and top up more often. Holding the level is the whole method. |
| CYA too high (over 80) | SLAM level becomes huge. Partial drain first, then SLAM. |
| Filter can't keep up | Clean the cartridge or backwash; recharge DE. Check the pump runs 24/7. |
| Phosphates or algaecide myths | Neither clears algae. Chlorine at SLAM level does. |
| Mustard or black algae | Brush hard daily, wash tools and toys, and expect it to take longer. |
Algaecide and flocculant are optional. Algaecide prevents but does not kill a bloom fast, and flocculant forces you to vacuum to waste. Chlorine, a brush and a running filter clear a green pool.
Sources
Figures and safety guidance on this page draw on the following public references.
- 1.U.S. Centers for Disease Control and Prevention. Healthy Swimming: Pool Chemistry & Disinfection
Free from skimmerpoolcare.com. Log today's test in Skimmer: Pool Care Log on the App Store.
General reference for residential pools. Product labels and local guidance override any figure here. See our methodology and editorial policy. Skimmer · skimmer pool care.