Problems & Tips

GREEN WATER TREATMENT: How to Kill Algae and Clear Your Pool

Algae can turn your pool green quickly—but with the right approach, you can bring it back to crystal-clear. This process typically takes a few days and works best when followed step by step.

Important Notes Before You Begin

Do not add algaecide while chlorine is high. High chlorine levels (above 5 ppm) will deactivate algaecides.
Use non-stabilized chlorine shock for best results—either Cal Hypo (73%) or Liquid Chlorine (Sodium Hypochlorite).
Leave the pool cover OFF to allow for maximum circulation and UV breakdown of waste products.
Algaecides don’t kill algae—they make algae more susceptible to chlorine.

DAY 1: Test & Balance Water

Before shocking, test and adjust your water:

Free Chlorine: 1–4 ppm
pH: 7.2–7.6
(Note: If pH is too high, shock will not be effective.)
Alkalinity: 80–120 ppm
Stabilizer (CYA): 60–80 ppm

DAY 2: Shock the Pool

Calculate the volume of your pool in gallons.
Add 2x the regular dose of Cal Hypo (73%) to reach a target Free Chlorine level of 30 ppm.
Keep the pump running 24/7.

DAY 3: Brush, Vacuum & Re-Shock if Needed

Dead algae will look like dirt or sand on the bottom of the pool.
Brush the walls and floor thoroughly.
Vacuum to waste if possible, or filter and backwash.
Test chlorine levels:
- If the pool is still green or chlorine has dropped to 0, shock again.
Clean or backwash the filter after vacuuming.

DAY 4: Final Steps

Backwash or clean your filter again.
Once Free Chlorine drops below 5 ppm, you may add algaecide if needed (optional).

Tips for Success

It’s virtually impossible to over-shock a pool during an algae treatment.
Expect the pool to look cloudy before it clears—this is normal.
If shocking isn’t working, a chlorine enhancer like sodium bromide may be used (follow label instructions).

What Causes High pH in a Swimming Pool?

1. pH Naturally Rises Over Time

Even without adding chemicals, pool pH tends to drift upward due to aeration and evaporation.

2. High Alkalinity

pH and total alkalinity are closely linked. If alkalinity is too high, it will push pH higher as well.
That’s why alkalinity should be adjusted before adjusting pH.

3. Algae Growth

Active algae in the pool can increase pH levels as it consumes carbon dioxide during photosynthesis.

4. Chlorine Products

Certain types of chlorine raise pH:

Calcium Hypochlorite (Cal Hypo)
Liquid Chlorine (Sodium Hypochlorite)

5. Salt Water Generators (SWG)

Saltwater pools tend to have higher pH due to the chemical byproducts of the electrolysis process.

Tip: Monitor Regularly

Frequent testing and adjusting is key to keeping pH balanced, especially if you use SWG systems or shock the pool often.

CLOUDY POOL WATER: Common Causes & How to Fix It

Cloudy water is one of the most common pool issues—and fortunately, it's often easy to fix once you identify the cause. Below are the main reasons it happens and how to clear it up.

Top 4 Causes of Cloudy Water

1. Poor Circulation

The #1 cause of cloudy water is inadequate water movement. If your pump isn’t running long enough or your return jet isn't positioned well, water may not be circulating properly. This allows debris and contaminants to build up.

2. Dirty or Ineffective Filters

Filters are the second most common cause:

Sand Filters: May need to be backwashed.
Cartridge Filters: If recently replaced, it likely needs to be rinsed off—especially if the pool has turned cloudy. A new filter can clog quickly as it collects debris.
Tip: Clean cartridges regularly and replace every 2–3 weeks during peak season.

3. Chemical Overlap or Improper Timing

If you add multiple chemicals too close together, it can cause cloudiness:

Always allow at least 24 hours between different treatments (except chlorine tablets).
Let each product dissolve and circulate fully before adding another.

4. Lack of Vacuuming

Vacuuming is essential—filters alone won’t remove all dirt or fine debris.

Even if the water looks clear at a glance, small particles can stay suspended and cause cloudiness.
Dirt often settles or stays in motion, making it hard to spot.

Other Possible Causes

High pH
High Alkalinity
High Chlorine (especially after shocking)
Inconsistent chlorine levels
Dead algae, pollen, or dust
Excess dirt and debris not removed by skimming or filtering

Pro Tip: Stir Up the Water Manually

If you're in the pool:

Walk in circles around the edge to create a centrifugal effect.
Do 5–6 loops, then stop and let the water settle.
Debris will gather in the center, making it easier to vacuum or skim with a fine silt net.

How to Clear Cloudy Water

Vacuum the Pool Thoroughly
Test and Balance the Water
- Adjust pH, alkalinity, and sanitizer as needed.
Keep the Pump Running Continuously for 24–48 Hours
Backwash or Clean Filters Frequently
- Every few hours for sand filters.
- Rinse cartridge filters regularly; replace every 2–3 weeks.
Leave the Pool Uncovered
- Promotes airflow and better circulation.
Be Patient After Shocking
- It’s normal for the water to turn cloudy for 1–2 days after an algae treatment.

Important Reminder

Always wait at least 24 hours before adding a different chemical or product. Mixing too soon can cause cloudy water—or worse, dangerous reactions.

METALS IN POOL WATER – WELL WATER WARNING

If you're filling your pool with well water, you're more likely to deal with metals, especially iron. While some filtration systems remove a portion of these minerals, iron is a common issue—particularly in rural areas or homes that rely on private wells.

What Happens When You Add Chlorine

At first, your pool water may look clear—even if metals like iron are present. But once you add chlorine, things change quickly:

Chlorine oxidizes the metals, causing them to change color.
Iron turns the water green or rusty brown.
It’s the same reaction you see when bleach touches silver—it darkens immediately.

How to Treat Metals in Pool Water

Option 1: Use a Metal-Removing Product

Products like Metal Out or metal sequestrants are designed to bind to metals in the water.
These are usually made with detergents, acids, and sequestering agents that help trap and remove metals.
Most require you to lower your pH before use for the product to be effective—adding to the overall cost.

Option 2: Use the Sock Trick (Cheap & Easy!)

One of the simplest and most affordable solutions uses items you already have at home:

What You Need:

A sock, tights, or thick nylon
Your pool’s return jet

How It Works:

Stretch the sock over the return jet—the outlet where water flows back into the pool from the pump.
Keep the pump running to circulate the water through the sock.
In just an hour or two, you’ll start to see the sock turn brown or green—that’s the metals being trapped in the fabric!

This DIY method is fast, simple, and effective—and a great first step if you’re not ready to buy specialty products.

Glossary of Terms

These are the not-so-scientific terms put simply so you will not require multiple PhDs to understand!

ACTIVE INGREDIENT Which chlorine compound and how much of the package is that compound.

AERATION Making bubbles to make air contact with water. Raises pH.

ALGAECIDES Help to kill active algae by breaking down the algae’s cell walls; microbial disinfectants / detergent

ALGAESTATS Preventative used to prevents algae

ALKALINITY pH buffer; keeps pH levels from bouncing up & down

AUTOMATIC VACUUM (POOL CLEANER) Vacuum that navigates itself.

AVAILABLE CHLORINE (PRODUCT LABEL) A comparison of the product’s chlorine to chlorine gas. Chlorine compounds made a standard in order to measure diff compounds. The standard is chlorine gas. Chlorine Gas is always 100%, so available chlorine is comparing to 100%

BACKWASH VALVE SETTING Cleans filter of dirt/debris particles

BALANCED WATER Maintained levels in water (pH, alkalinity, chlorine, & stabilizer); when these levels are in good range

BBB Method of cleaning pool using Bleach, Borax, Baking Soda and Muriatic Acid

BIGUANIDES Biguanides (PHMB) are chlorine-free sanitizing liquid that binds bacteria molecules tighter into clumps for the filter to catch.

BLEACH Sanitizer, has same main ingredient Sodium Hypo as liquid chlorine with lower concentration.

BORATES pH buffers, act as an algeastat and increase chlorine performance

BROMINE Sanitizer, used in warmer water.

CALCIUM Calcium content of water

CAL-HYPO (CALCIUM HYPOCHLORITE) Unstabilized chlorine shock with calcium; 10ppm Chlorine + 7ppm Calcium

CELLULOSE FIBER Biodegradable, nontoxic filter for DE systems; also as a filter aid for cartridge filters.

CHLORAMINES Product of combined chlorine; the chlorine smell in a pool

CHLORINE Sanitizer; cleans the water

CHLORINE BREAK POINT / BREAKPOINT CHLORINATION Amount of chlorine required to destroy all combined chlorine in water (add chlorine amount equivalent to 10x amount of combined

CHLORINE CONCENTRATION How concentrated main ingredient molecule is

CHLORINE DEMAND How much chlorine is needed to clean all organic matter in the pool; contaminants like algae use up chlorine that should be working on other contaminants.

CHLORINE ENHANCER Makes chlorine more effective against hard to treat algae in pool water

CHLORINE LOCK Stabilizer levels are so high it causes chlorine to stop working

CLARIFIER Liquid that is designed to clump tiny (visible & invisible) particles of dirt/contaminants together to make it easier for filter to catch

CLEANING Remove dirt, dust, crumbs, and germs off the surfaces and objects.

CLOSE/WINTER VALVE SETTING Stops and closes all flow to filter

COMBINED CHLORINE Chlorine molecules have attached to dirt/debris and started sanitizing

CONTAMINANTS Dirt, debris, particles, microorganisms, bacteria etc. in water

CYANURIC ACID (CYA/STABILIZER) Protects Chlorine from being burned off by sun

DICHLOR Stabilized chlorine 10ppm chlorine + 9ppm CYA

DISINFECTING Kills bacteria and viruses identified on the product’s label on hard surfaces.

DRY ACID (SODIUM BI SULFATE) Lowers pH and/or Alkalinity

ENZYMES Enzymes act by speeding up chemical reactions.

FILL WATER The water used to fill the pool

FILTER VALVE SETTING Cleans water by pushing through filter (leaving dirt in filter) then back to pool

FLOW RATE The time it takes to circulate all of the water through the filter one time.

FREE CHLORINE Chlorine molecules available to clean/sanitize the water; molecules have not attached to contaminants and started cleaning yet (FC, FAC, Free available chlorine, available chlorine)

GPH Gallons that flow through in one hour per hour

GPM Gallons that flow through in one minute

GFCI PLUG Ground Fault Circuit Interrupter. Built-in circuit breaker.

HARDNESS Level of minerals like Calcium, Iron and Magnesium and metals are in the water.

HYPERCHLORINATION Completely disinfect; raise FC to 20-40 ppm for a certain period of time

IONIZERS Used to lower chlorine usage by releasing silver/copper ions into water to stop bacteria growth

MINERAL SANITIZERS Introduce mineral into the water to act as sanitizer

MURIATIC ACID Lowers pH and/or Alkalinity

NON-CHLORINE SHOCK Oxidation breaks down organics without chlorine.

O-RINGS Round rubber gasket the seals connections from leaking water.

OXIDATION Breaks down contaminants by using oxygen; not the same as disinfection or sanitization, but is part of disinfecting or sanitizing.

pH How acidic the water is

PHOSPHATE REMOVER Enzyme product added to remove phosphates from the water

PLUNGER Plungers stop water from pool to hoses/pump; like turning off a faucet.

POLYQUAT ALGAECIDE Attach to algae, & quickly spread over the cell and smother the algae. More effective and longer lasting than standard algaecides. Do not foam or stain.

PPM Measurement, Parts per million

PUMP Motorized device that pushes water

RECIRCULATE VALVE SETTING Circulates water without the filter

RESIDUAL CHLORINE Amount of chlorine left in pool after the meeting chlorine demand

RINSE VALVE SETTING Flushes filter system by pushing water through filter & out to waste. Settles filter media and prevents it from going back into pool

SALINITY Amount of salt level in the water of salt pools. 2700 - 4500 ppm.

SALT Used by saltwater generator to convert salt to generate chlorine

SANITIZER Chlorine, Bromine, etc.

SANITIZING Lowering the number of germs to a safe level (cleaning, disinfecting, or both)

SCALE Crust hardness on surface caused by high calcium, pH or alkalinity levels

SEQUESTRANT Stain inhibitor; holds metals & minerals in solution, preventing them from oxidized or harmful to pool water.

SHOCK Superchlorination; adding high concentration of chlorine to eliminate all combined (10-20ppm)

SKIMMER Accessory/add-on that skims the dirt from the top of the pool

SODA ASH (SODIUM CARBONATE) Raises pH, will raise Alkalinity slightly.

SODIUM BICARBONATE (BAKING SODA) Used to raise alkalinity & slight increase in pH

SODIUM BISULFATE (DRY ACID) Chemical used to lower the pH and total alkalinity.

SODIUM HYPOCHLORITE Liquid chlorine, unstabilized, normally 10-12% available chlorine

SODIUM BROMIDE Chlorine enhancer, common in algaecides

STABILIZER/CYA (CYANURIC ACID) Protects Chlorine from being burned off by sun

STABILIZED CHLORINE Chlorine with stabilizer/CYA – (dichlor, trichlor)

STAIN Discolored water or liner; usually caused by metals in pool water

STERILIZATION Kills all germs/ microorganisms

SUPERCHLORINATION (SHOCKING) Adding high concentration of chlorine to eliminate all combined (10-20ppm)

SWG (SALTWATER GENERATOR) Converts salt to chlorine. The SWG does NOT replace the pump or filter, instead is an additional piece of equipment that goes between the filter and the pool.

TOTAL CHLORINE Free Chlorine + Combined Chlorine

TOTAL DISSOLVED SOLIDS (TDS) Evaporated/dissolved material in the water

TRICHLOR Stabilized chlorine compound; 10ppm chlorine + 6ppm CYA

TURNOVER RATE How many times the water goes through the filter in one day (24 hours).

VACUUM (CLEANER) Collects dirt from pool floor either using suction, pressure from pump or hose or has self-sustained power (rechargeable)

WASTE VALVE SETTING Pushes water of valve bypassing filter

WINTERIZING Steps taken to store and protect pool through winter months without draining it.