Seasonal Guide
Opening your pool after winter doesn't have to be stressful. Follow these steps in order and you'll be swimming in clean, clear water by the weekend.
Open your pool when daytime temperatures consistently stay above 70°F (21°C). In most parts of the US, that's late March to early May depending on your region. Opening too late lets algae get a head start under the cover. Better to open a week early than a week late.
Clean the pool cover
Remove standing water and debris from the cover before taking it off. Any dirt on the cover will fall into the pool otherwise.
Remove and store the cover
Pull the cover off carefully. Clean it with a hose, let it dry completely, then fold and store it out of sunlight. A dry cover lasts years longer.
Remove winterizing plugs
Remove any plugs from return jets and skimmers. Replace with the normal fittings.
Reinstall equipment
Reconnect the pump, filter, heater, salt cell, or any equipment you disconnected for winter. Check for cracks or damage.
Fill the pool to normal level
Water drops over winter. Fill to the middle of the skimmer opening using your garden hose.
Prime and start the pump
Open the air relief valve on the filter, turn on the pump, and let it prime. Close the air valve once water flows steadily.
Check for leaks
Walk around the equipment pad and look for drips at every connection. Tighten anything that's weeping. A small winter crack can become an expensive problem fast.
Run the pump for 24 hours
Let the water circulate a full day before testing chemistry. This mixes everything and lets the filter start catching debris.
Clean the filter
Backwash a sand or DE filter, or remove and hose off cartridge filters. Start the season with a clean filter so it can handle the initial load.
Skim and vacuum
Skim floating debris. If there's a lot of sediment on the bottom, vacuum to waste (bypassing the filter) so you don't clog it immediately.
Test the water
Test free chlorine, pH, total alkalinity, calcium hardness, and CYA. Everything will likely be off after winter. That's normal.
Adjust alkalinity first (80–120 ppm)
Add baking soda to raise it. Add muriatic acid to lower it. Wait 4 to 6 hours between adjustments and retests.
Adjust pH (7.2–7.6)
Soda ash to raise, muriatic acid to lower. If you adjusted alkalinity with acid, pH may already be in range.
Shock the pool
Add enough chlorine to reach 10 ppm (shock level). This kills anything that grew over winter. Run the pump overnight.
Adjust calcium hardness (200–400 ppm)
Add calcium chloride if low. If high, you may need to drain some water and refill.
Check CYA (30–50 ppm)
Add stabilizer if low. CYA doesn't degrade over winter, so it might still be fine from last season.
Retest after 24 hours
After the shock has dissipated and the water has circulated, test again. Fine-tune as needed.
Brush the walls and floor
Brush every surface, even if it looks clean. This knocks off any early algae spores and helps the chlorine reach everything.
Set up your maintenance schedule
Decide when you'll test (at least weekly) and when you'll add chemicals. Consistency prevents most problems.
Check safety equipment
Make sure the fence gate self-closes and latches, the pool alarm works, and you have a life ring or reaching pole accessible.
Wait for chlorine to drop below 5 ppm
Don't swim until free chlorine is back to 5 ppm or lower after shocking. Usually takes 24 to 48 hours.
Opening your pool is a lot easier when you don't have to memorize dosing amounts. Pool Clarity takes your post-winter test results and tells you exactly what to add, how much, and in what order. Free to use.
Open My Pool with Pool Clarity →