Complete Usage Guide
What each chemical does, when to use it, how much to add, and how to apply it safely. Your quick reference for every pool chemical in your shed.
Sanitisers
Stabilised chlorine contains cyanuric acid (stabiliser) which protects the chlorine from being destroyed by UV sunlight. It's the most common form of chlorine for regular pool sanitation. Use it to maintain a free chlorine level of 1 to 3 ppm at all times.
| When to use | Daily or as needed to maintain chlorine levels. Add in the evening so chlorine works overnight without UV loss. |
|---|---|
| How to apply | Pre-dissolve in a bucket of pool water, then pour slowly around the pool perimeter with the pump running. Never throw granules directly into the pool as they can settle and bleach the surface. |
| Target level | 1 to 3 ppm free chlorine. Test before adding. Add only what is needed. |
| Dosage guide |
Formula: ((3 โ current FC) ร 20) ร (pool volume รท 10,000) grams Example: A 40,000L pool at 0.5 ppm FC needs approximately 200g to reach 3 ppm. Note: Add in smaller increments and retest. Easier to add more than to correct an overdose. |
| Simplified |
๐ก Quick estimatePer 10,000L: About 40g of granules raises chlorine by 1 ppm. Typical 40,000L pool: If chlorine is very low (0.5 ppm), add about 200g (roughly 1 level cup, depending on density). Retest after 4 hours. Add another 50-100g if needed. Always pre-dissolve in a bucket first. Use the calculator for your specific pool. |
| Important notes | Stabilised chlorine adds both chlorine and stabiliser. Over time stabiliser levels can build up. If stabiliser exceeds 80 to 100 ppm, chlorine becomes less effective. Use unstabilised chlorine (liquid or cal-hypo) periodically if stabiliser is high. |
๐งฎ For exact doses, use the calculator
Match your test strip colour and enter your pool volume for a precise dosage tailored to your pool. Open Calculator โ
Water Balancers
Dry acid lowers pH and total alkalinity. It's a safer, easier-to-handle alternative to liquid pool acid. Use when pH tests above 7.6. High pH reduces chlorine effectiveness and can cause scaling and cloudy water.
| When to use | When pH tests above 7.6. Add in small increments and retest after 4 to 6 hours. |
|---|---|
| How to apply | Pre-dissolve in a bucket of pool water. Pour around the pool perimeter with the pump running. Do not add near pool fittings or in the skimmer. |
| Target level | pH 7.2 to 7.6 |
| Dosage guide |
Formula: ((current pH โ 7.6) ร 10 ร 100) ร (pool volume รท 10,000) grams Example: A 40,000L pool at pH 8.2 needs approximately 240g of dry acid to reach 7.6. Note: Add half the calculated dose first, retest after 4 hours, then add more if needed. Always add acid to water. |
| Simplified |
๐ก Quick estimatePer 10,000L: About 60g of dry acid lowers pH by roughly 0.1 (e.g., from 8.0 to 7.9). Typical 40,000L pool: If your pH is 8.2, start with about 100-120g (roughly half a cup) dissolved in a bucket. Pour it in, retest after 4 hours. Add another 60-100g if still above 7.6. Go slow. It's easier to add more than to overshoot. Use the calculator for your specific pool. |
| Important notes | Safer to store and handle than liquid acid. Produces no fumes. Ideal for regular pH maintenance. Add small amounts. It's easier to add more than to correct an overshoot. |
๐งฎ For exact doses, use the calculator
Match your pH test strip colour and enter your pool volume for a precise dosage. Open Calculator โ
Liquid hydrochloric acid is the strongest and fastest way to lower pH and alkalinity. It's commonly used for pH control in larger pools and for cleaning salt cells and surfaces. It requires careful handling due to its corrosive nature.
| When to use | When pH tests above 7.6, or when total alkalinity needs significant reduction. Also used for cleaning salt cells (see chlorinator guide) and surfaces. |
|---|---|
| How to apply | Dilute in a bucket of pool water (always add acid to water, never water to acid). Pour slowly near a return jet with the pump running. Wear gloves and eye protection. |
| Target level | pH 7.2 to 7.6. Add in small amounts and retest. |
| Dosage guide |
Liquid acid is approximately 3x stronger than dry acid. Use roughly one-third the dry acid dose as a starting point. Example: For a 40,000L pool, start with approximately 80 to 100ml of liquid acid, retest after 4 hours. Note: Always add acid to water, never water to acid. Add small amounts. You cannot undo an overdose. |
| Simplified |
๐ก Quick estimatePer 10,000L: About 25ml of liquid acid lowers pH by roughly 0.1. Typical 40,000L pool: If your pH is 8.2, start with about 80ml (about โ of a standard measuring cup) diluted in a full bucket of pool water. Always pour acid into the water in the bucket, not the other way around. Retest after 4 hours. Add another 50ml if needed. Wear gloves and goggles every time. Use the calculator for your specific pool. |
| Important notes | Highly corrosive. Store upright in a cool, ventilated area away from chlorine and other chemicals. Never mix with chlorine. It produces toxic gas. For routine pH adjustment, dry acid is a safer option. |
Total alkalinity acts as a buffer that prevents rapid pH changes. If alkalinity is too low, pH will swing wildly. If it's too high, pH becomes difficult to adjust. Maintaining alkalinity between 80 and 120 ppm stabilises your water chemistry.
| When to use | When total alkalinity tests below 80 ppm. Correct alkalinity first before adjusting pH. Alkalinity acts as the foundation. |
|---|---|
| How to apply | Pre-dissolve in a bucket of pool water. Pour around the pool perimeter with the pump running. Add in increments and retest after 4 to 6 hours. |
| Target level | 80 to 120 ppm total alkalinity |
| Dosage guide |
Formula: ((80 โ current TA) รท 10) ร 180) ร (pool volume รท 10,000) grams Example: A 40,000L pool at 40 ppm TA needs approximately 2,880g (2.88kg) to reach 80 ppm. Note: Add in two doses, 4 hours apart. Raising alkalinity will also raise pH slightly. Adjust pH after alkalinity is correct. |
| Simplified |
๐ก Quick estimatePer 10,000L: About 180g of alkalinity buffer raises TA by 10 ppm. Typical 40,000L pool: If your TA is 40 ppm and target is 80 ppm, you need about 2.9kg. That's about 3 full 1kg bags or roughly 9-10 cups (depending on density). Split into two doses a few hours apart. Retest after 4-6 hours. Fix alkalinity first, then adjust pH. Use the calculator for your specific pool. |
| Important notes | Alkalinity and pH are linked. Raising alkalinity will also raise pH slightly. Always test both. Adjust alkalinity first, then fine-tune pH. This is the foundation of balanced pool water. |
๐งฎ For exact doses, use the calculator
Match your alkalinity test strip colour and enter your pool volume for a precise dosage. Open Calculator โ
Calcium hardness is the measure of dissolved calcium in your pool water. Low calcium levels cause water to become aggressive and corrosive, leaching calcium from pool surfaces, grout, and equipment. This is especially important for concrete, pebble, and tiled pools.
| When to use | When calcium hardness tests below 200 ppm. Common in areas with soft water or after heavy rain dilution. |
|---|---|
| How to apply | Pre-dissolve in a bucket of pool water. Pour around the pool perimeter with the pump running. Add in increments and retest after several hours. |
| Target level | 200 to 400 ppm for concrete/pebble pools. 150 to 250 ppm for fibreglass/vinyl pools. |
| Dosage guide |
Formula: ((250 โ current hardness) รท 10) ร 15) ร (pool volume รท 10,000) grams Example: A 40,000L pool at 100 ppm hardness needs approximately 900g to reach 250 ppm. Note: Add in increments. Large calcium adjustments should be split across 2 to 3 doses, 24 hours apart. Retest between doses. |
| Simplified |
๐ก Quick estimatePer 10,000L: About 15g of calcium hardness up raises hardness by 10 ppm. Typical 40,000L pool: If your hardness is 100 ppm and target is 250 ppm, you need about 900g (roughly 4 cups). Split into two doses a day apart. Retest before adding the second dose. Concrete pools need more calcium than fibreglass. Use the calculator for your specific pool. |
| Important notes | Low calcium is corrosive. High calcium causes scaling. Both extremes damage equipment and surfaces. Test first, then adjust. Fibreglass and vinyl pools need less calcium than concrete pools. |
๐งฎ For exact doses, use the calculator
Match your hardness test strip colour and enter your pool volume for a precise dosage. Open Calculator โ
Stabiliser protects chlorine from being destroyed by UV sunlight. Without stabiliser, the sun can destroy up to 90% of your free chlorine within a few hours. Stabiliser is essential for outdoor pools using chlorine. Indoor pools do not require stabiliser.
| When to use | When cyanuric acid tests below 30 ppm. Also required when starting a fresh fill or after significant water replacement. |
|---|---|
| How to apply | Do not pre-dissolve. Add granules directly to the skimmer basket with the pump running, or hang in a sock in front of a return jet. Do not backwash for 48 hours after adding. Dissolves slowly. Allow several days to fully dissolve. |
| Target level | 30 to 50 ppm. Do not exceed 50 ppm. Too high stabiliser reduces chlorine effectiveness. |
| Dosage guide |
Formula: ((30 โ current CYA) รท 10) ร 100) ร (pool volume รท 10,000) grams Example: A 40,000L pool at 0 ppm CYA needs approximately 1,200g (1.2kg) to reach 30 ppm. Note: Add to skimmer basket or hang in a sock near a return jet. Do not backwash for 48 hours. Dissolves over several days. |
| Simplified |
๐ก Quick estimatePer 10,000L: About 100g of stabiliser raises CYA by 10 ppm. Typical 40,000L pool: If your CYA is 0 ppm and target is 30 ppm, add about 1,200g (1.2kg) (roughly 6 cups) into the skimmer basket with the pump running. Don't backwash for 48 hours. It dissolves slowly over several days. Don't add more until you've retested. Stabiliser doesn't break down. Use the calculator for your specific pool. |
| Important notes | Stabiliser does not dissipate. It stays in the water until diluted by splash out, backwashing, or rain overflow. If you use stabilised chlorine regularly, test stabiliser monthly as levels can creep up. Too high stabiliser (above 80 to 100 ppm) requires partial drain and refill to reduce. |
๐งฎ For exact doses, use the calculator
Match your stabiliser test strip colour and enter your pool volume for a precise dosage. Open Calculator โ
Metal remover binds to dissolved metals (iron, copper, manganese) in pool water, preventing them from oxidising and causing brown, green, or black stains on pool surfaces. It's especially important when filling from bore water, well water, or in areas with known metal content in the water supply.
| When to use | When filling from bore/well water. When you notice brown, green, or black staining on pool surfaces. As a preventative treatment if your water source is known to contain metals. After adding chlorine shock if metals are present. |
|---|---|
| How to apply | Follow product-specific dosing. Pour around the pool perimeter with the pump running. Most metal removers are liquid and work immediately. |
| Target level | No specific test level. Use as directed on the product label for your pool volume. |
| Dosage guide |
Follow the dosing instructions on the product label for your pool volume. Metal removers are dosed based on pool size, not a specific test level. Typical initial dose: 500ml per 50,000L for most products. Check your specific product label. |
| Simplified |
๐ก Quick estimatePer 25,000L: About 250ml (half a standard bottle) for most products. Typical 40,000L pool: Start with about 400ml of metal remover. Pour it in with the pump running. If stains are already present, use a stain remover first, then add metal remover to stop them coming back. Always check the label on your specific product. Doses vary by concentration. |
| Important notes | Metal remover binds metals but does not remove them from the water. The metals remain in solution. Over time, you may need to re-dose. If stains are already present, use a stain remover first, then apply metal remover to prevent re-staining. |
Chlorine remover rapidly reduces free chlorine levels when they are too high. Use after shock treatments if you need to swim sooner, or if chlorine levels have been accidentally overdosed. It works within minutes.
| When to use | When free chlorine tests above 5 ppm and you need to swim. After a shock treatment when chlorine is slow to drop naturally. If chlorine has been accidentally overdosed. |
|---|---|
| How to apply | Pre-dissolve in a bucket of pool water. Pour around the pool perimeter with the pump running. Add small amounts. You can always add more but you cannot undo an overdose. |
| Target level | 1 to 3 ppm free chlorine. Test before and after adding. |
| Dosage guide |
Follow the dosing instructions on the product label. Chlorine remover dosage varies by product concentration. Note: Add in small increments and retest after 30 minutes. If you don't need to swim urgently, chlorine will naturally drop with sunlight exposure. |
| Simplified |
๐ก Quick estimatePer 50,000L: About 50-60g (roughly ยผ cup) of chlorine remover lowers chlorine by about 5 ppm. Typical 40,000L pool: If your chlorine is off the chart, start with about 40-50g dissolved in a bucket. Pour it in, wait 30 minutes, retest. If still too high, repeat with another 40g. If you're not in a rush, the sun will burn off excess chlorine for free in 1-2 days. Always check your product labelโconcentrations vary. |
| Important notes | Chlorine remover is a precise chemical. Add in small increments and retest after 30 minutes. It's easier to add more than to correct an overshoot. If you don't need to swim urgently, chlorine will naturally drop over time with sunlight exposure. |
Shock & Oxidisers
Oxi shock is a non-chlorine oxidiser that burns off organic waste (sweat, sunscreen, body oils) without adding chlorine. It reactivates existing chlorine by breaking down chloramines (combined chlorine). Those are the compounds that cause chlorine smell and eye irritation. It allows swimming almost immediately after use.
| When to use | Weekly as a preventative shock to keep water clear. After heavy pool use or parties. When you notice chlorine smell (which is actually chloramines, not chlorine). When combined chlorine exceeds 0.5 ppm. |
|---|---|
| How to apply | Pre-dissolve in a bucket of pool water. Pour around the pool perimeter with the pump running. Add in the evening for best results. |
| Target level | Dose according to pool volume on the product label. Weekly maintenance dose is typically lower than heavy-use dose. |
| Dosage guide |
Typical weekly maintenance: 500g per 50,000L. After heavy use: 500g per 30,000L to 40,000L. Note: Oxi shock does not replace chlorine. It oxidises waste to free up your existing chlorine. For a green pool, use chlorine shock instead. |
| Simplified |
๐ก Quick estimatePer 25,000L: About 250g (half a standard 500g bottle) for weekly maintenance. Typical 40,000L pool: Add about 400g (most of a 500g bottle) as a weekly treatment. After a pool party, use the full 500g bottle. Pre-dissolve in a bucket, pour around the edge with the pump running. If your pool smells strongly of chlorine, it actually needs a shock. That smell is spent chlorine, not fresh chlorine. Oxi shock fixes it. |
| Important notes | Does not sanitise. It oxidises. Oxi shock does not kill algae or bacteria. For a green pool, use chlorine shock instead. Swimming can resume shortly after use (check product label). Ideal for regular maintenance between chlorine shocks. |
Specialty Chemicals
Clarifier causes tiny particles suspended in the water to clump together so they can be captured by the filter. It's used for mild to moderate cloudiness where you can still see the bottom of the pool. Results typically appear within 24 to 48 hours.
| When to use | When pool water is mildly to moderately cloudy but you can still see the bottom. After addressing the cause of cloudiness (often pH imbalance or insufficient filtration). |
|---|---|
| How to apply | Follow product dosing for your pool volume. Pour around the pool perimeter with the pump running. Most clarifiers are liquid. Run the pump for at least 8 hours after dosing. |
| Target level | Dose according to product label. Do not overdose. Too much clarifier can make cloudiness worse. |
| Dosage guide |
Follow the dosing instructions on the product label for your pool volume. Clarifier dosage varies by product. Typical dose: 250 to 500ml per 50,000L for most clarifiers. Check your specific product label. |
| Simplified |
๐ก Quick estimatePer 25,000L: About 125-250ml (ยฝ to 1 cup) for most clarifiers. Typical 40,000L pool: Add about 200-400ml (roughly 1 to 1.5 cups) depending on the product. Pour around the edge with the pump running. Run the pump for at least 8 hours. Make sure your filter is clean before you start. A dirty filter can't catch anything. Check your product labelโdoses vary by concentration. |
| Important notes | Clarifier works with your filter. Ensure your filter is clean before using. A dirty filter cannot capture the clumped particles. If water is very cloudy or you cannot see the bottom, use floc instead. Clarifier is for maintenance; floc is for severe cloudiness. |
Floc is a stronger version of clarifier for severely cloudy pools where you cannot see the bottom. It binds particles together into heavy clumps that sink to the pool floor rather than passing through the filter. The clumps must then be vacuumed to waste.
| When to use | When pool water is severely cloudy and you cannot see the bottom. After addressing the cause of severe cloudiness. When clarifier has not worked. |
|---|---|
| How to apply | Follow product dosing. Pour around the pool perimeter with the pump running. Then turn the pump OFF and let the water sit undisturbed for 12 to 24 hours. The floc will settle to the bottom. Vacuum the settled material to WASTE (not through the filter). Top up pool after. |
| Target level | Dose according to product label for your pool volume. |
| Dosage guide |
Follow the dosing instructions on the product label for your pool volume. Typical dose: 1kg per 50,000L for most floc products. Check your specific product label. Do not overdose. |
| Simplified |
๐ก Quick estimatePer 25,000L: About 500g (half a 1kg bag) for most floc products. Typical 40,000L pool: Use about 800g (most of a 1kg bag). Add it with the pump running for 10 minutes, then turn the pump OFF. Walk away for 12-24 hours. The floc will drag everything to the floor. You must vacuum this to WASTE, not through your filter. If your system does not have a waste setting, do not use floc. Use clarifier instead. Check your product labelโdoses vary by concentration. |
| Important notes | Floc requires the pump to be turned OFF so particles can settle. You must be able to vacuum to waste. If your system cannot vacuum to waste, use clarifier instead. Floc is a more involved process but produces dramatic results for severely cloudy water. |
Calcium hardness down chemically reduces high calcium levels without the need to drain and refill the pool. High calcium causes scaling on pool surfaces and equipment, cloudy water, and reduced chlorinator efficiency. This product is especially useful in hard water areas.
| When to use | When calcium hardness tests above 400 ppm (concrete/pebble) or above 250 ppm (fibreglass/vinyl). When you notice white scale deposits on surfaces or equipment. |
|---|---|
| How to apply | Follow product-specific dosing for your pool volume and current calcium reading. Pour around the pool perimeter with the pump running. Retest after 24 to 48 hours. |
| Target level | 200 to 400 ppm for concrete/pebble pools. 150 to 250 ppm for fibreglass/vinyl pools. |
| Dosage guide |
Formula: ((current hardness โ 350) รท 25) ร 500) ร (pool volume รท 10,000) ml Example: A 40,000L pool at 600 ppm hardness needs approximately 2,000ml (2L) to reduce to 350 ppm. Note: Add in two doses, 24 hours apart. Retest between doses. The only alternative to reduce calcium is partial drain and refill. |
| Simplified |
๐ก Quick estimatePer 10,000L: About 500ml of calcium down reduces hardness by roughly 50 ppm. Typical 40,000L pool: If your hardness is 600 ppm and target is 350 ppm, start with about 1,000ml (1L) (half a bottle) in the first dose. Pour it in, run the pump, retest after 24-48 hours. If still high, add the other half. If the product doesn't bring it down enough, the only other fix is to partially drain and refill with softer water. Check your product labelโdoses vary by concentration. |
| Important notes | Prevention is better than treatment. If you live in a hard water area, test calcium regularly. The only other way to reduce calcium is partial drain and refill with softer water. Calcium hardness down is a chemical alternative that avoids water waste. |
๐งฎ For exact doses, use the calculator
Match your hardness test strip colour and enter your pool volume for a precise dosage. Open Calculator โ
๐งค Always wear gloves and eye protection when handling pool chemicals. Even mild chemicals can irritate skin and eyes.
โ๏ธ Never mix chemicals. Add each chemical separately to the pool, at least 30 minutes apart with the pump running. Mixing chemicals, especially chlorine and acid, produces toxic gas.
๐ง Always add chemicals to water, never water to chemicals. This is especially critical with acid products. Adding water to concentrated chemicals can cause violent reactions.
๐ฆ Store chemicals separately. Keep chlorine products away from acid products. Store in a cool, dry, well-ventilated area. Keep out of reach of children. Keep lids tightly sealed.
๐ Pre-dissolve granular chemicals in a bucket of pool water before adding to the pool. Never throw granules directly into the pool where they can settle on the surface and cause damage.
โฑ๏ธ Add chemicals with the pump running to ensure rapid dilution and distribution. Run the pump for at least 2 hours after adding most chemicals.
๐ Test before you treat. Always test your water before adding any chemical. Guessing leads to over-dosing, unbalanced water, and wasted chemicals.
๐งฎ Use the calculator at mrpoolman.com.au/pages/pool-chemical-calculator-water-technix for exact dose calculations tailored to your pool.
๐ Emergency: Poisons Information 13 11 26. If chemicals contact eyes, rinse thoroughly for 15 minutes and seek medical attention.
๐งช Pool Chemical FAQs
The correct order is: 1. Alkalinity (adjust first. It's the foundation). 2. pH (adjust second. It's affected by alkalinity). 3. Calcium hardness. 4. Stabiliser (if needed). 5. Chlorine (add last). Wait at least 30 minutes between each chemical with the pump running. Always test before adding anything.
No. Never mix pool chemicals, especially chlorine and acid. Mixing produces toxic chlorine gas which can cause severe respiratory injury. Add each chemical separately to the pool, at least 30 minutes apart. Always add chemicals to water, not water to chemicals.
Use our free calculator at mrpoolman.com.au/pages/pool-chemical-calculator-water-technix. Match your 7-in-1 test strip colours, enter your pool volume, and get instant personalised dosage recommendations. Alternatively, use the dosage formulas and simplified guides in each chemical card above. Doses scale with pool volume. A 40,000L pool needs 4x the dose of a 10,000L pool.
Stabilised chlorine (dichlor/trichlor) contains cyanuric acid which protects chlorine from UV destruction. It's ideal for regular outdoor pool maintenance. Unstabilised chlorine (liquid chlorine, calcium hypochlorite) does not contain stabiliser. Use unstabilised chlorine for shock treatments or if your stabiliser level is already high. Salt chlorinators produce unstabilised chlorine, which is why stabiliser must be added separately to salt pools.
If your water is mildly cloudy and you can see the bottom, use clarifier. It works with your filter to remove particles. If your water is severely cloudy and you cannot see the bottom, or clarifier hasn't worked, use floc. Floc settles particles to the floor and requires vacuuming to waste. If you cannot vacuum to waste, stick with clarifier.
Stabiliser does not dissipate or evaporate. It stays in the water permanently and only leaves through splash out, backwashing, or overflow from rain. If you regularly use stabilised chlorine (dichlor/trichlor), stabiliser levels will steadily increase. Switch to unstabilised chlorine or liquid chlorine periodically to prevent buildup. If stabiliser exceeds 80 to 100 ppm, you will need to partially drain and refill the pool.
For routine pH maintenance, dry acid (sodium bisulphate) is safer and easier to handle. It produces no fumes, is less corrosive, and is ideal for regular use. Liquid acid (hydrochloric) is stronger and faster-acting. It's better suited for large pH adjustments, cleaning tasks, and commercial pools. Both achieve the same result. Choose based on your comfort level and the size of adjustment needed.
It depends on what you added. For most balancing chemicals (pH, alkalinity, calcium), wait 2 to 4 hours with the pump running. For chlorine, wait until the level is 1 to 3 ppm. Test before swimming. For shock treatments, wait until chlorine drops below 5 ppm. For oxi shock, you can swim almost immediately (check product label). For floc, wait 24 hours and vacuum to waste before swimming. Always test before swimming.
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