Opening your pool after winter is one of those jobs that's either quick and painless or a total nightmare — and the difference usually comes down to whether you follow a good sequence. Do it in the right order and you can be swimming within a day or two. Skip steps or do them out of order and you're looking at a week of fighting green water.
Here's the full sequence, in order.
When to Open Your Pool
The right time is when overnight temperatures consistently stay above 50°F (10°C). Opening too early means fighting algae in cold water before you're really using it. Opening too late means a bigger algae problem to clean up. In most northern states, late April to mid-May is the sweet spot.
What You'll Need
- Pool brush and vacuum
- Test kit or test strips
- Shock (cal-hypo or liquid chlorine)
- Algaecide
- pH adjuster (muriatic acid or pH up)
- Alkalinity increaser (baking soda) if needed
- Stabilizer/CYA if needed
- Filter cleaner
Step-by-Step Opening Process
1
Remove and clean the cover
Pump off standing water before removing it. Clean both sides, let it dry completely, then store it — a wet cover stored folded will mold quickly. Inspect for tears while you're at it.
2
Reconnect equipment
Reinstall any equipment you removed for winter — return jets, skimmer baskets, ladders, handrails. Remove any winter plugs from returns. Reconnect the pump and filter.
3
Top up the water level
Water level should be at the middle of the skimmer opening. If it's low from winter, run a hose before starting the pump.
4
Clean the filter
Before starting the system, clean your filter. Backwash a sand filter, clean a cartridge filter, or recharge a DE filter. Starting the season with a clean filter makes everything easier.
5
Start the pump and check for leaks
Prime the pump if needed, then turn it on. Walk around and check all fittings and connections for leaks. Let it run for 30 minutes before doing anything else.
6
Skim, brush, and vacuum
Remove all debris from the water. Brush the walls, floor, and steps thoroughly. Vacuum to waste if there's a lot of sediment (bypasses the filter so you don't clog it immediately).
7
Test the water
Test pH, alkalinity, chlorine, CYA, and calcium hardness. Write down the results — you need all of them before adding anything. Don't skip this step and just start dumping chemicals in.
8
Balance alkalinity first, then pH
Get alkalinity to 80-120 ppm using baking soda if it's low, or muriatic acid if it's high. Then adjust pH to 7.2-7.6. Always do alkalinity before pH — alkalinity affects pH stability.
9
Shock the pool
Use 2 lbs of cal-hypo per 10,000 gallons for opening shock. Add at dusk. Run the pump overnight. This kills any algae or bacteria that built up over winter.
10
Add algaecide
The day after shocking, add a maintenance dose of algaecide. This provides ongoing protection as you get chemistry stabilized for the season.
11
Add stabilizer if CYA is low
If CYA is below 30 ppm, add granular stabilizer to bring it to 40-50 ppm. Add it to a sock in the skimmer basket or pre-dissolve it. CYA takes 24-48 hours to fully register on a test.
12
Retest and fine-tune
Test everything again after 24-48 hours. Make any final adjustments. Once chlorine is between 1-3 ppm and everything else is in range — you're ready to swim.
💡 Opening a green pool? If your pool is already green when you open it, follow the green pool fix guide first before balancing chemistry — you'll need significantly more shock.
How Long Until You Can Swim?
If the pool was covered and chemistry was in decent shape at closing: 1-2 days. If there's algae or the water has been sitting uncovered: 3-5 days. The filter running continuously is the key — the more it runs, the faster it clears.
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Wade walks you through the opening process based on your specific pool and tells you exactly what chemicals to add in what amounts. No guesswork, no wasted chemicals.
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