Green Pool After Vacation in The Colony — Fast Recovery Plan

You were gone for eight days. The pool was crystal clear when you left. You did everything right — shocked the night before departure, loaded the chlorinator, set the pump timer for 12 hours. And now you're standing at the pool edge looking at water the color of split pea soup, wondering how eight days turned a perfect pool into a swamp.

The Colony's proximity to Lewisville Lake plays a direct role in how fast an unattended pool deteriorates. The lake-effect humidity keeps the air moist, which supports biological activity around and above the pool surface — mold spores, algae spores, and airborne bacteria all thrive in humid conditions. While your neighbor's pool in drier, inland Allen might survive 10 days of neglect with minor cloudiness, a Colony pool in Austin Waters, Stewart Peninsula, or The Tribute is operating in a more biologically aggressive environment. The margin for error is narrower.

For pre-vacation preparation tips to prevent this from happening next time, see our guide on keeping your pool clear while on vacation.

Assess the Damage: What Shade of Green?

The color tells you how far the bloom has progressed and determines the recovery approach.

Light Green or Teal Tint

What it means: Early-stage algae. Chlorine depleted 2-3 days ago and algae has just established. The water is hazy but you can still see the bottom in the shallow end.

Recovery time: 24-48 hours.

Approach: Standard shock dose (1 pound cal-hypo or 1 gallon liquid chlorine per 10,000 gallons), run the filter 24/7, brush everything, retest the next morning. This is the easy version — if chlorine holds above 2 ppm the next morning, the bloom is dead and the filter will clear the dead cells within a day.

Medium Green (Opaque — Can't See Bottom)

What it means: Active algae bloom. Chlorine has been at zero for 3-5 days. Algae is fully established in the water column and on surfaces. The water is opaque — you can't see deeper than a foot or two.

Recovery time: 2-4 days.

Approach: Double or triple shock dose. Aggressive brushing. Continuous filtration with multiple filter cleanings. This is the most common post-vacation scenario for Colony pools in summer.

Dark Green, Brown-Green, or Black-Green

What it means: Severe bloom. Chlorine has been absent for 5+ days and the algae population is dense. The water may have a musty or swampy smell. Dark green or brown tones indicate dead algae mixed with living algae — the bloom is mature.

Recovery time: 4-7 days.

Approach: Maximum shock dose. Potentially a partial drain if the water is so contaminated that chemical treatment would be excessively expensive. Full multi-day recovery protocol.

The Fast Recovery Protocol

Step 1: Physical Removal First (30-60 Minutes)

Before adding a single chemical, remove as much physical debris as possible:

Skim the surface. Green water often has a thick layer of floating organic material — dead insects, pollen accumulation, surface algae film. Remove it all.

Brush everything aggressively. Walls, floor, steps, behind ladders, around returns, the waterline. Brushing breaks algae's grip on surfaces and suspends it in the water where chlorine and the filter can reach it. Use a stainless steel brush for plaster/gunite — nylon brushes are too soft to disrupt established algae.

Empty the skimmer basket and pump basket. They're probably full after 8 days. Full baskets restrict flow, and you need maximum flow for the recovery.

Check and clean the filter. Start with a clean filter — if it's already dirty going into the recovery, it won't last through the heavy filtration demand ahead. Clean the cartridge, backwash the sand/DE, whatever your filter needs. You'll be cleaning it again during the recovery — starting clean buys you more run time before the first mid-recovery cleaning.

Step 2: Test the Water (10 Minutes)

Test free chlorine, pH, and alkalinity at minimum.

Expected readings for a green post-vacation pool:

• Free chlorine: 0 (or very near it — the algae consumed everything)
• pH: Unpredictable — could be high (from algae metabolism raising pH) or low (from rain dilution during the trip)
• Alkalinity: Likely drifted, possibly low from rain

Don't test CYA right now — it doesn't change during a vacation and isn't actionable during recovery. Test it after the pool is clear and you're rebuilding the maintenance routine.

Step 3: Fix pH Before Shocking (15 Minutes)

Shock is most effective at lower pH. If pH is above 7.4, add muriatic acid to bring it to 7.2 before shocking. If pH is already at or below 7.2, leave it alone.

Don't adjust alkalinity yet. Get the pool clear first, then fine-tune alkalinity afterward. Trying to balance everything simultaneously during a green pool recovery wastes chemicals and complicates the process.

Step 4: Shock Hard (15 Minutes)

For a medium-green 15,000-gallon Colony pool, the shock dose is:

Triple shock: 3 pounds of calcium hypochlorite OR 3 gallons of 12.5% liquid chlorine. This should bring free chlorine to approximately 25-30 ppm — far above normal maintenance levels, but that's the point. The algae bloom represents a massive chlorine demand. You need enough chlorine to overwhelm the demand, kill the algae, and still have residual chlorine left over.

Use liquid chlorine if your calcium hardness is above 350 ppm. Cal-hypo adds calcium — and in Colony pools that may already have elevated calcium from summer evaporation, liquid chlorine avoids stacking more calcium into an already hard-water situation.

Add the shock after sunset. UV destroys unstabilized chlorine, and you need every milligram working on the algae — not being consumed by sunlight.

Run the pump 24/7 starting now. Don't turn it off until the pool is clear. Continuous circulation ensures the shock reaches every corner of the pool and pushes dead algae through the filter.

Step 5: The Overnight Wait

Go to bed. Let the chlorine and the pump do the work overnight.

Step 6: Morning Assessment (Day 2)

Test free chlorine first thing.

FC above 5 ppm: The shock overwhelmed the algae demand. The water should be transitioning from green to cloudy gray or cloudy white — that's dead algae cells suspended in the water. This is progress. Keep the pump running.

FC at 0-2 ppm: The algae demand consumed most of the shock. The bloom was heavier than the initial dose could handle. Shock again at the same dose — tonight, after sunset. This isn't uncommon for post-vacation Colony pools in summer where the humidity-accelerated bloom was particularly dense.

Brush again. Any algae clinging to surfaces after the overnight shock needs to be disrupted and suspended.

Check filter pressure. If it's risen 8-10 psi above clean baseline, the filter is loaded with dead algae. Clean it now and put it back in service. Don't wait — a clogged filter stops clearing the water no matter how much chlorine you add.

Step 7: Days 2-4: Filter and Monitor

The transition from green to clear follows a predictable color sequence:

Green → cloudy green → cloudy gray → cloudy white → haze → clear

This progression takes 2-4 days with continuous filtration and adequate chlorine. Each stage means progress. If the color reverses (going from cloudy gray back to green), chlorine has dropped to zero again — shock immediately.

Monitor chlorine daily. Add supplemental liquid chlorine as needed to maintain FC above 5 ppm during the recovery. Don't let it drop below 2 ppm until the water is clear — the remaining dead and dying algae will regrow if chlorine disappears before the recovery is complete.

Clean the filter every time pressure rises 8+ psi. During a heavy algae recovery, you may clean the filter 2-3 times over the course of the clearing process. Each cleaning restores flow and filtration capacity.

Step 8: Post-Recovery Rebalance

Once the water is clear (you can see the main drain clearly from the surface):

• Lower chlorine target back to 2-3 ppm (it'll come down naturally as you stop adding shock)
• Test and adjust pH to 7.2-7.6
• Test and adjust alkalinity to 80-120 ppm
• Test CYA — if you used stabilized shock (dichlor), CYA may have climbed. If it's above 60 ppm, note it for a future partial drain
• Clean the filter one final time
• Resume normal pump schedule and chemical routine

What the Recovery Costs

For a typical medium-green Colony pool recovery:

Item	Cost
Liquid chlorine (3-6 gallons over 3-4 days)	$20-50
Muriatic acid (pH correction)	$5-10
Electricity (pump running 24/7 for 3-4 days)	$10-25
Filter cartridge (if damaged by heavy load)	$0-100
Total DIY recovery	$35-185
Professional recovery service	$150-350

A professional recovery handles the chemistry, brushing, filter cleaning, and daily monitoring — saving you 3-4 days of checking the pool twice daily and making adjustments. The cost premium over DIY is essentially paying for your time and the expertise to recover efficiently without overcorrecting.

Preventing the Next Vacation Green-Out

The pre-trip checklist in our vacation pool care guide covers the preparation details. The Colony-specific additions:

Consider a mid-trip service visit. For vacations longer than 7 days during summer, a single professional visit on day 4-5 — testing chemistry, adding chlorine, emptying baskets, checking equipment — can prevent the entire recovery scenario. One service visit costs $50-100. A post-vacation recovery costs $150-350 plus your first weekend back.

Run the salt cell at 70% output during travel (if equipped). The higher-than-normal output compensates for the absence of supplemental shocking during the trip. Monitor salt levels before departure — the cell can't produce chlorine without adequate salt.

Install a liquid chlorine feeder for extended trips. These gravity-fed devices dispense liquid chlorine from a reservoir at a controlled rate. More precise than tablet floaters and adds zero CYA. Cost: $100-300 for the unit.

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Don't want to come home to a green pool? Hydra Pool Services offers vacation coverage — maintaining your Colony pool on schedule while you travel — across The Colony, Frisco, Plano, McKinney, Allen, Murphy, and Parker. Set up travel coverage →