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Seasonal readiness

Opening / Closing Supplies Calculator

Use this to shop and stage the work. It is not a green-water cleanup plan, a drain plan, or a replacement for a real test.

Opening and closing

Inputs

Enter what you know right now. Leave FC or CYA blank if you do not have a reliable result.

Checklist updates automatically

Opening plan

Use this list to stage the job before you mix chemicals, run the heater, or close the cover.

Opening
Pool size
20,000 gallons equivalent
FC raise estimate
81.9 fl oz of 12.5% liquid chlorine
4.0 ppm FC rise

Testing

  • Borrow, buy, or schedule a reliable test before dosing
    Opening kits and startup bundles are not substitutes for a result set.
  • Retest salt and inspect the cell after circulation
    Salt systems need a startup check after the water mixes.
  • Retest after the pump has circulated the water
    Use the mixed reading before any second adjustment.

Safety

  • Wear gloves and eye protection when handling chemicals
  • Keep chlorine and acid separate; never mix pool products
  • Confirm barriers, gates, ladders, covers, and drain covers before swimmers return
  • Keep swimmers out when the bottom or main drain is not clearly visible
  • Protect exposed plumbing and equipment from freezing
  • Keep the cover hardware and winter accessories together

Cleaning

  • Skim debris, empty baskets, and brush the walls, steps, and corners
  • Vacuum settled debris before you trust the chemistry
  • Pump or sweep dirty cover water away before it reaches the pool
  • Clean the cartridges and inspect the seals
  • Use filtration and clarity checks before you call the pool ready

Chemistry

  • Use the FC and pH readings to decide what to add next
    Do not buy or add a full startup bundle without matching each product to a measured need.
  • Plan liquid chlorine from the measured FC gap only
    4.0 ppm rise at 12.5% strength.
  • Retest CYA after circulation before changing stabilizer again
  • Confirm salt level and cell condition after startup
  • Correct the water condition before chasing a target dose
  • Retest CH after opening if the pool was winterized or partially drained

Equipment

  • Pump lid O-ring, drain plugs, skimmer baskets, and return fittings
  • Pressure gauge, valve positions, and clean-filter baseline
  • Cover reel or clean storage bin for the removed cover
  • Cover clips, straps, or the cover itself as needed
  • Freeze-protection settings or a low-temperature pump schedule

Retest reminders

  • Use a reliable test before dosing anything.
  • Retest CYA after the water mixes.
  • Recheck salt and cell status after startup.
  • Recheck CH after opening if winter water changes or refill water are involved.
  • Clear the water and retest before you add more chlorine.

Limits

  • This is not a substitute for actual testing.
  • Do not shock blindly or treat a startup bundle as a diagnosis.
  • Green water, floodwater, sewage, or visible equipment damage needs a different workflow before normal opening.
  • Winter chemicals and winterizing steps are manual-specific.
  • Avoid drain advice here; follow your pool and equipment manual for any water-level changes.

Educational guidance only. Verify labels, manuals, local code, and site conditions before acting. Stop for electrical, gas, structural, drain, drowning, injury, emergency, or chemical-mixing risk.

Terms