Green Pool Recovery

Woke up to a swamp? Don’t drain it, fix it fast. A green pool is just algae plus poor balance/filtration. With the correct sequence (and a little patience), you can go from pea soup to crystal clear in a couple of days. Here’s Pool Life’s proven, step-by-step playbook.

Green Pool Recovery – Why pools turn green

• Low sanitiser: Free chlorine (FC) dropped too low for your stabiliser (CYA) level.
• Poor circulation/filtration: Dirty filter, short run times, blocked baskets, or air leaks.
• Unbalanced water: High pH reduces chlorine’s effectiveness.
• Debris & nutrients: Leaves, dust, storm runoff and phosphates feed algae.
• Heat & UV: Sunlight accelerates chlorine burn-off; warm water speeds algae growth.

Before you start: safety & tools

Safety: Wear gloves and eye protection. Never mix chemicals. Always add acid to water, not the other way around. Keep products cool, dry, ventilated, and out of reach of kids and pets.

Tools & supplies:

• Quality test kit (FC, pH, TA, CH, CYA; salt if applicable)
• Liquid chlorine (sodium hypochlorite) or cal-hypo shock
• Pool acid (to set pH ~7.2)
• Algae brush (stiff for concrete, soft for vinyl/fibreglass)
• Clarifier or flocculant (optional, see step 6)
• Leaf rake, manual vacuum & hose (even if you use a robot)

The Pool Life “Green-to-Clean” plan

Step 1 — Restore circulation (10–15 min)

• Remove large debris with a leaf rake; empty skimmer & pump baskets.
• Set valves correctly; prime the pump (no air in the lid).
• Ensure the water level is 2/3 up the skimmer opening.

Why: Algae dies faster when chemicals and water move.

Step 2 — Check & set pH (~7.2) (5–10 min)

• Test pH. If it’s high, add small doses of pool acid to bring it to a pH of around 7.2.
• Circulate 30–60 minutes and re-test.

Why: Chlorine is far more effective at lower pH (but still within the safe range).

Step 3 — Shock hard (and smart)

• Add a large, initial dose of chlorine. For most residential pools, this is 10–20 ppm FC, depending on your stabiliser (CYA).
• Salt pools: Your chlorinator can’t raise FC fast enough on its own—use liquid chlorine for the initial hit, then let the cell maintain.

Tip: Distribute around the pool with the pump running. Avoid pouring through the skimmer if you use a tablet feeder or have metals.

Step 4 — Brush like you mean it (10–20 min)

• Brush walls, steps, corners, behind ladders and especially the waterline.
• Expect the water to turn cloudy grey/white as algae breaks up—this is good.

Why: Brushing disrupts the biofilm, so chlorine contacts the organism directly.

Step 5 — Filter 24/7 and babysit FC (Day 1–2)

• Run the pump continuously during recovery.
• Backwash the sand/DE filters when the pressure rises 8–10 psi above the clean pressure.
• Cartridge filters: Hose off when pressure increases or flow drops.
• Test FC every 4–8 hours on Day 1; top up chlorine to maintain a high level until the water lightens from green to a dull blue/grey.

Goal: Maintain a killing level of FC until algae is dead, not just faded.

Step 6 — Clear the clouds (optional)

Once the water is grey/blue but murky:

• Option A: Clarifier (easy mode): Helps micro-particles clump so the filter can catch them. Keep filtering; clean the filter as needed.
• Option B: Floc (fast mode): For heavy debris or parties looming. Turn off the pump overnight after dosing; particles settle to the floor, and then vacuum them slowly to waste the next day, so you don’t stir them up. You’ll lose some water—top up and rebalance after.

Note: Never use clarifier and floc at the same time.

Step 7 — Fine-tune chemistry (after it’s blue but hazy)

• Re-test and correct, in this order: → 1) TA (buffer) → 2) pH → 3) CH → 4) CYA → 5) FC
• For salt pools, verify that the salinity is within the chlorinator’s specifications.
• Keep pH 7.2–7.6, FC in range for your CYA, and run time long enough to stay clear.

Special cases

Mustard/Yellow algae: Likes shady spots and returns after “normal” shocks. After clearing, raise FC to the high end for your CYA for 24–48 hours. Brush daily and expose toys, poles, cleaners, and swimsuits to chlorinated water or direct sunlight.

Black spot algae (concrete pools): Very stubborn. Requires repeated brushing with a stainless brush, locally applied chlorine or an algaecide suited to black algae, and sustained high FC. Expect a multi-week campaign.

Metals & staining: If water turns brown on shocking, you may have iron. Use a sequestrant and avoid big pH swings; consider partial dilution. Treat stains after the algae is gone.

Timelines: what to expect

• Day 0: Green → teal after shock & brush.
• Day 1: Cloudy blue/grey; filter working hard; FC still high.
• Day 2–3: Noticeable clearing; fine silt on floor; normal FC maintenance resumes.
• Day 3–5: “Polish” phase—water goes from clear to sparkling.

(Extreme blooms, undersized/dirty filters, or very high CYA can extend this.)

Prevention: keep it from coming back

• Match FC to CYA: As stabiliser rises, chlorine needs increase. Don’t let CYA creep too high.
• Run enough hours: Especially in hot, sunny weather. Variable-speed pumps: run longer on low.
• Brush weekly: Cheapest algaecide there is.
• Control debris & nutrients: Scoop leaves early; consider phosphate remover if you have recurring blooms and heavy organic loads.
• Watch pH drift: If pH rises rapidly, check TA and aeration sources (including spillovers and water features).
• Log your tests: Trends reveal issues before they’re visible.

What Pool Life’s Green-to-Clean service includes

• On-site diagnosis: Full water test (FC, CC, pH, TA, CH, CYA, salt), circulation audit, and filter assessment.
• Targeted treatment plan: Correct pH, calculate shock levels, use algaecide only when necessary, and manage phosphates as needed.
• Mechanical clean: Professional brush, debris removal, vacuum (including vacuum-to-waste when floc is used).
• Filtration optimisation: Backwash/clean, pressure baseline set, run-time programming for season and bather load.
• Follow-through: Return visit or remote check to ensure you hit “sparkling,” plus a simple prevention checklist tailored to your pool.

Prefer not to wrestle with a swamp? Pool Life can transform your pool from green to clean, fast, and then keep it that way.

Quick FAQ

Can I just drain and refill?
Only as a last resort. Draining can float fibreglass or crack concrete, and it’s often unnecessary (and costly).

Will my salt chlorinator fix a green pool by itself?
Not quickly. Use liquid chlorine for the initial recovery, then let the chlorinator maintain.

Is floc safe for my filter?
Yes, when vacuumed to waste. Don’t run floc through cartridge elements or DE grids—they can gum up.

How soon can we swim?
When water is clear, FC is within normal range, and pH is 7.2–7.6. Always test before diving in.