Pool Opening After Winter

Introduction

Spring has arrived and it's time to wake your pool from its winter slumber. Opening the pool after hibernation is a crucial moment that determines how your entire swimming season will go. A well-executed process means crystal-clear water from day one; a poorly done process can result in weeks of battling algae and cloudy water.

Many owners underestimate the importance of this phase. After months of inactivity, the pool accumulates dirt, the water chemistry changes, and the equipment needs to be checked. Skipping steps or doing things out of order can cause problems that persist all summer.

In Margem Sul, where winters are relatively mild but still have periods of intense rain, pool opening usually happens between March and April. In this article, we present a complete step-by-step guide to opening your pool correctly, ensuring a trouble-free swimming season.

When to Open the Pool

The Ideal Time

Choosing the right moment is important:

Why Not to Wait Too Long

Opening the pool earlier has advantages:

• Fewer algae: Lower temperatures hinder growth
• Cleaner water: Less time to accumulate dirt
• Equipment tested: Time to resolve problems before the heat
• Gradual preparation: Water chemistry stabilises progressively

Materials Needed

Checklist

Before starting, gather everything you need:

Cleaning equipment:

• Surface net (leaf skimmer)
• Wall brush
• Pool vacuum
• Garden hose
• Bucket

Chemicals:

• Water test kit (pH, chlorine, alkalinity)
• Shock chlorine (calcium hypochlorite or dichloroisocyanurate)
• pH adjuster (acid or base)
• Algaecide
• Flocculant/clarifier
• Chlorine stabiliser (cyanuric acid)

Protective equipment:

• Rubber gloves
• Safety goggles
• Appropriate clothing

Other:

• Silicone lubricant
• Spare O-rings
• Teflon tape

Step by Step: Opening the Pool

Step 1: Remove and Clean the Cover

Procedure:

1. Remove debris from the cover

• Use a net to remove leaves and accumulated water
• Don't let dirt fall into the pool
• Pump out standing water if necessary

1. Remove the cover carefully

• Ask for help with large covers
• Fold carefully avoiding tears
• Avoid dragging on the ground

1. Clean the cover

• Wash with water and mild detergent
• Let dry completely
• Check for damage to repair

1. Store correctly

• Store in a dry, cool place
• Protect from rodents
• Avoid direct sun exposure

Step 2: Inspect the Pool

Visual checks:

Immediate actions:

• Fill pool to correct level before turning on equipment
• Note any damage for repair
• Photograph problems for reference

Step 3: Prepare the Filtration System

Pump room:

1. Remove winter plugs

• Remove plugs from pipes
• Remove plugs from returns and skimmers
• Store plugs for next winter

1. Inspect the pump

• Check strainer pot condition
• Clean strainer basket
• Check lid O-ring (lubricate with silicone)
• Check electrical cables

1. Prepare the filter

• Set multiport valve to "Filter"
• Check pressure gauge (if damaged, replace)
• Open suction and return valves

1. Check additional equipment

• Heater: check connections and condition
• Salt chlorinator: clean cell if needed
• Dosing pump: check tubes and operation
• Lighting system: test before swimming

Step 4: Start Filtration

Start-up procedure:

1. Prime the pump (if necessary)

• Fill strainer pot with water
• Close lid firmly
• Open suction valve

1. Turn on pump

• Check for water flow
• Observe if strainer pot fills
• Confirm no leaks

1. Check operation

• Returns working?
• Skimmers drawing?
• Filter pressure normal?

1. Do initial backwash

• Cleans dirt accumulated in filter
• Backwash for 2-3 minutes
• Rinse for 30 seconds
• Return to "Filter"

Common start-up problems:

Step 5: Initial Cleaning

Debris removal:

1. Surface

• Use leaf skimmer net
• Remove all floating material
• Make several passes

1. Walls

• Brush all walls from top to bottom
• Focus on stained areas
• Brush the waterline

1. Bottom

• Let debris settle (1-2 hours)
• Vacuum to waste (not to filter)
• If very dirty, vacuum on "Waste" mode

1. Skimmer and strainer

• Clean baskets frequently during this process
• Initial dirt is abundant

Step 6: Water Analysis and Treatment

Initial tests:

Test the following parameters:

Treatment procedure:

1. Correct pH first

• If high: use dry acid or muriatic acid
• If low: use sodium carbonate
• Wait 4-6 hours and test again

1. Adjust alkalinity

• If low: sodium bicarbonate
• If high: muriatic acid (also lowers pH)

1. Shock treatment

• Use shock chlorine (calcium hypochlorite recommended)
• Dosage: 10-15g per 1000L of water
• Apply at end of day
• Let filter for 24 hours

1. Add algaecide

• Preventive after shock
• Dosage per product instructions
• Wait 24h after chlorine shock

1. Clarify if needed

• Use flocculant if water cloudy
• Let work and vacuum the precipitate

Step 7: Stabilisation

First 48-72 hours:

• Keep filtration running 24h/day
• Test water 2x daily
• Adjust products as needed
• Don't use pool until values stabilise

Signs it's ready:

• Crystal clear water (see bottom clearly)
• pH between 7.2-7.6
• Chlorine between 1-3 ppm
• No strong chlorine smell
• No irritation when wetting hand

Special Cases

Pool with Green Water

If the pool opened with very green water:

1. Assess severity

• Light green: strong shock treatment
• Dark green: may need partial draining
• Green with black: probably black algae

1. Intensive treatment

• Brush all surfaces well
• Shock chlorine at 20-30g/1000L
• Shock algaecide
• Continuous filtration
• Vacuum precipitate to waste

1. Repeat if necessary

• May need 2-3 treatments
• Test and adjust daily

Saltwater Pool

For pools with salt electrolysis:

1. Check salt level (before turning on unit)
2. Clean the cell (limescale deposits)
3. Test the cell (check chlorine production)
4. Only turn on when water is clean
5. Adjust production gradually

Pool with Damaged Cover

If cover let water and debris through:

• Expect to find more dirt
• May need partial draining
• Check for liner damage
• Prepare for more intensive treatment

Final Equipment Check

Complete Checklist

Initial Preventive Maintenance

Take the opportunity to:

• Lubricate O-rings with silicone
• Tighten loose connections
• Replace worn parts
• Calibrate measuring equipment
• Program timers

Opening Schedule

7-Day Plan

Accelerated Plan (3-4 days)

For those in a hurry (water in good condition):

• Day 1: Everything up to shock
• Day 2: Continuous filtration, adjustments
• Day 3: Clarification, final tests
• Day 4: Ready for use

Typical Opening Costs

Do It Yourself

Professional Service

Common Mistakes to Avoid

The 10 Most Frequent Mistakes

1. Running pump without enough water → Damages mechanical seal
2. Adding chlorine before correcting pH → Chlorine ineffective
3. Not brushing before shock → Algae protected
4. Vacuuming too much dirt to filter → Clogs filter
5. Using pool before stabilising → Eye irritation
6. Not checking equipment → Undetected problems
7. Forgetting to remove winter plugs → Pipe damage
8. Adding all products at once → Chemical reactions
9. Not filtering long enough → Cloudy water
10. Ignoring small leaks → Bigger problems

Frequently Asked Questions

How long does it take to open a pool?

With water in good condition, 3-5 days until ready for swimming. With green or very dirty water, it can take 7-10 days or more. The physical cleaning process takes 1-2 days; chemical stabilisation needs more time.

Can I use the pool right after shocking?

No. You should wait until chlorine drops to normal levels (1-3 ppm), usually 24-48 hours. High chlorine levels cause skin and eye irritation.

Is green water always algae?

Usually yes, but it can also be oxidised metals (especially copper or iron). Well water often causes green colouration from metals. A specific test can differentiate.

Do I need to drain the pool to open it?

Rarely. Only in extreme cases of contamination or when liner repairs are needed. Most pools are opened by treating the existing water.

When should I call a professional?

If you find structural damage, if the pump doesn't work, if water doesn't clear after several treatments, or if you simply prefer to ensure everything is done correctly.

Conclusion

Opening the pool after winter is a methodical process that requires patience and attention to detail. Key points for a successful opening are:

• Choose the right time – when temperature starts rising consistently
• Follow the correct order – physical cleaning before chemical treatment
• Correct pH before chlorine – for maximum effectiveness
• Filter enough – at least 24h continuous after shock
• Test regularly – until water stabilises
• Check all equipment – prevent problems during the season

If you need professional help with your pool in Margem Sul, ManutençãoPiscinas is here to help. Contact us for a no-obligation quote.