When to open your pool in Laval — the complete 2026 guide

The ideal opening date in Laval

In the Laval, Montreal and North Shore region, the optimal opening window is May 10 to June 1. Simple rule: open when water sits above 12 °C for 3 days in a row.

You can wait until end of May. You can also open May 10 if the weather cooperates. What matters is the water, not the calendar.

Why not earlier. Cold water slows filtration. The winter cover keeps leaves and debris warm. Algae start growing at 15 °C.

Why not later. The longer water sits under the cover, the worse it turns. A shock treatment in June costs more than opening in May.

The steps of a proper opening

1. Remove the winter cover. Drain accumulated water, brush off leaves, wash the cover with soapy water, let dry before storing.
2. Reinstall equipment. Filter hoses, ladder, skimmer basket, pump basket.
3. Top up the water to mid-skimmer level.
4. Plug in and start the filter. Run a full 12–24 hour cycle.
5. Test the water. Chlorine, pH, total alkalinity, hardness, stabilizer.
6. Adjust: alkalinity first (80–120 ppm), pH next (7.2–7.6), chlorine last (1–3 ppm).
7. Vacuum the bottom. Robot or manual brush.
8. First shock if needed. 1 lb of chlorine per 10,000 gallons.

What it costs in Laval in 2026

Packages usually include equipment, water test and basic chemistry. Green-water rescues need more product and more filter cycles.

Your water is already green. What now?

Salvageable. Here's the order:

1. Don't put the cover back on. Sun helps oxidize.
2. Triple-dose shock. 3 lbs of chlorine per 10,000 gallons.
3. Brush walls and floor. Dislodge dead algae.
4. Filter 24h non-stop. Clean the filter every 8 hours.
5. Vacuum to waste, not through the filter. Top up water during.
6. Re-test. Often a second shock is needed.

For a really gone pool (opaque green, can't see the bottom), rescue takes 3–5 days and $300–$600 in chemicals alone. A pro service can do it in 2 visits.

Common mistakes

1. Opening at 8 °C. Too cold for chemistry to react. You'll redo everything.
2. Adding chlorine before adjusting pH. Chlorine loses up to 50% efficacy at an off pH.
3. Forgetting stabilizer (cyanuric acid). Without it, sun destroys your chlorine in hours.
4. Not brushing walls. Algae embed in the liner pores.
5. Filtering only 4 hours/day the first week. Need 12–24 hours until water is clear.

We can handle the opening

Our opening package includes cover removal and cleaning, equipment reinstall, filter startup, full water test and balance, and first cleaning. We leave a written report with water state and doses added.

Get a quote for pool opening →