We’ve gone over pool chemicals quite a bit over the past few blog posts, but they’re spread out and are located in specific posts where they’re required. So today, we’re going to go over ALL the chemicals you’ll ever use in your pool and we’re going to make a handy guide where you can easily look up everything you wanted to know about a specific pool chemical. Put on your thinking caps as we will now start our Masterclass on pool chemicals with Mr Pool Man’s Ultimate Guide to Pool Chemicals.

How To Safely Use Pool Chemicals


  • Wear protective equipment and do not inhale the fumes
  • Immediately wash any part of your body that comes in contact with any pool chemical
  • NEVER COMBINE ANY CHEMICAL WITH ANY OTHER POOL CHEMICAL as this may cause poisonous chemical fumes or even explosions
  • Do not combine same types of chemicals from different manufacturers. Each manufacturer will have their own specifications and may or may not have additives that may not play well with each other
  • Use separate measuring cups for each type of chemical as residue from other chemicals can still cause dangerous chemical reaction
  • Ensure that your scoops and measuring cups are bone-dry before using it on any chemical as moisture can cause a chemical reaction
  • ALWAYS Add pool chemicals to water and never the other way around
  • Check the production / Best by labels before using. Expired chemicals may have unintended results. If you find any expired chemicals then dispose according to local regulations.
  • Check and replace labels that are starting to fade so you’ll always know what container contains what.
  • If a label is faded and you do not know what a chemical does, properly dispose of it



  • Keep all chemicals in cool, dark places away from the elements
  • Ensure that storage area has proper ventilation as chemicals may release fumes even if they’re stored in air-tight containers
  • Keep any chemicals away from pets and children
  • Store oxidizers away from acids. If these two mix, it may produce poisonous chlorine gas
  • Never stack containers
  • Never store liquid chemicals above dry chemicals
  • Never store products in locations out of reach (overhead, etc) where additional help is needed to reach (stepladders, ladders, boxes). Or anywhere that poses a fall hazard.
  • Never reuse chemical containers. We know pool chemical containers look good and they’re pretty sturdy (they should be) but never reuse them for any purpose as the chemicals have already leeched into the plastic


First Aid for Accidents

  • Remove any article of clothing that may have been contaminated to reduce further contamination
  • Flush the area with running water (a garden hose will do) for at least 15 minutes. Do not delay this as the more time passes, the more “burned” the area will be
  • If the condition does not improve, call for medical assistance and be sure to identify the source of the contamination so appropriate treatment can be administered


Are pool chemicals bad for you?

Yes, and no.

Pool chemicals in their pure forms are very dangerous. This is why we previously laid out a whole section on safety precautions for using pool chemicals before this and that's why many of the bottles have very strict safety warnings.

But, properly used in your pool, they're about as harmless as the chemicals in your tap water (your mileage may vary! haha). But all kidding aside, one of the reasons that we write about pool chemicals so much is that, with the proper usage, they make your pool safe to use!

Specific Pool Chemical Guides

Unstabilised Chlorine

Unstabilised Chlorine is your basic chlorine without stabilisers or Cyanuric acid added to it. Cyanuric acid is added to chlorine to protect it from UV rays, making it last longer in your pool and prevents it from being burned off by the sun’s UV rays, this is especially true in Australia where for some reason the sun seems closer to than any other point on earth (not really scientific, but it sure feels that way!)

Now you might be asking why use unstabilised chlorine when there’s a stabilised version available right? Well, the reason for this is that too much cyanuric acid can lead to a condition called a “chlorine lock” which basically means that your chlorine is rendered useless. Here are some situations where unstabilised chlorine is recommended over stabilised chlorine.

  • For indoor pools and spas – No sun or UV rays means you don’t have to protect your chlorine from getting burned off
  • For shocking your pool – There will be situations where you’ll need increased levels of chlorine for short periods of time.
  • For topping up during heavy use – For times with high pool usage like pool parties or during the summer months where you need that extra bit of chlorine to properly sanitise your pool.


Chlorine Levels to shoot for – 1 to 3 PPM

How Much to Add - 15 grams of unstabilised chlorine for every 10,000 liters of water to raise by 1 PPM

How to add unstabilised chlorine – Dilute the unstabilised chlorine in a bucket of pool water and broadcast around the pool for even spreading. Never add unstabilised chlorine directly into your pool skimmer boxes as the high concentration of chlorine can damage your pool equipment.

Pump / Filter Status – Your pump and filter should be in place when adding chlorine to your pool. Keep your pool pump running for at least 8 hours (up to 24 hours) after adding chlorine to make sure the it is properly circulated around your pool.

How long before you can swim after adding unstabilised chlorine – A rule of thumb is to check your chlorine’s pool level after 4 hours after adding unstabilised chlorine. Once the chlorine level is below 5 PPM then it is safe to swim in the pool. If the chlorine level is still above 5 PPM then patience is the key, test again after 4 hours or to be totally safe, 24 hours after the application.

READ MORE: How To Maintain Chemicals In Peak Season

Stabilised Chlorine

Stabilised chlorine is basically chlorine with stabiliser or cyanuric acid added to it. This is the chlorine of choice for regular maintenance as it tops up your chlorine and cyanuric acid levels at the same time. This is for when both chlorine levels have dropped due to water spill outs (excessive cannonballs!) or after heavy rains where rainwater has diluted both the chlorine levels and cyanuric acid levels of your pool.

Chlorine Levels to shoot for – 1 to 3 PPM

How Much to stabilised chlorine to add - 15 grams of stabilized chlorine for every 10,000 liters of water to raise the chlorine level by 1 PPM

How to add stabilised chlorine – Dilute the stabilised chlorine in a bucket of pool water and broadcast around the pool so that it will be circulated faster and to avoid pockets of highly concentrated chlorine.

Pump / Filter Status – After adding stabilised chlorine, keep your pump running for at least 8-10 hours to ensure that it is properly circulated throughout your pool.

How long can you swim after adding stabilised chlorine – Much like unstabilised chlorine, you can check your pool water after 4 hours to see if the chlorine levels have dropped down to under 5 PPM. Once it’s below that level then it’s perfectly safe to swim in your pool.

Cyanuric Acid or UV Blockout

Cyanuric acid is the “stabilised” part of stabilised chlorine. Cyanuric acid is added to the pool if your chlorine levels are already at optimal levels and you just need to add that extra layer of protection to make the chlorine last longer. In fact, a study has shown that without cyanuric acid, over 50% of free chlorine will be burned out by UV rays in just under 20 minutes!

Cyanuric Acid Levels to shoot for – 30 to 50 PPM

How much Cyanuric Acid to Add - 100 grams of cyanuric acid or UV blockout should raise the cyanuric acid levels of 10,000 liters of water by 10 PPM.

How to Add Cyanuric Acid or UV Blockout – Make sure to clean your filter cartridges or backwash your sand filter before adding cyanuric acid. Dissolve the cyanuric acid in a small bucket of pool water then add directly to your skimmer boxes. Make sure that the granules are totally dissolved before adding to ensure that there wouldn’t be any clogs. If your cyanuric acid comes in tablets, simply drop the required dosage into your skimmer boxes.

Pump / Filter Status – After adding your cyanuric acid, keep the pump running for at least 8 hours for the cyanuric acid to fully circulate around your pool. Do not clean or backwash your filters for at least 48 hours to allow the cyanuric acid to be fully dissolved. Even though it looks like it’s fully dissolved, there are still microscopic bits that will take a bit longer to be dissolved.

How long can you swim after adding cyanuric acid – Cyanuric acid or UV blockout is relatively safe for swimmers so you can take a dip in your pool 20 minutes after adding it to your skimmer baskets.

Alkalinity Up or Sodium Bicarbonate

Alkalinity up or Sodium Bicarbonate is added to your pool to serve as a buffer, preventing wild pH level swings that can affect the effectivity of your other pool chemicals. It is also used to reduce the acidity in your pool and increase the alkalinity levels.

Alkalinity Levels to Shoot for – 80 to 140 PPM

How much Alkalinity Up or Sodium Bicarbonate to use - 200g of sodium bicarbonate for every 10,000 liters to raise the pool’s total alkalinity up by 10 PPM. Add them in small increments so that you won’t overshoot your desired Alkalinity levels, it’s easier to add more, but it takes so much effort to bring the levels down and rebalance your pool.

How to add Alkalinity up or Sodium Bicarbonate – After determining the required amount, carefully broadcast the powder all over the pool, avoid dumping in one place to ensure that it dissolves quickly and evenly.

Pump / Filter Status – Allow the pool pump to run for at least an hour after adding alkalinity up to your pool.

How long can you swim after adding Sodium bicarbonate or alkalinity up – Sodium bicarbonate or baking soda is generally harmless so you can take a swim in your pool 20 minutes (or maybe an hour if anyone is sensitive to it) after application of sodium bicarbonate.

Hydrochloric Acid

Hydrochloric acid is a liquid that has a clear and colorless appearance. Hydrochloric acid is added to a pool to reduce its pH levels.

WARNING: Hydrochloric acid is highly corrosive. Keep away from children and never handle without any protective equipment.

Note: Laws and Regulations prohibit the sale and shipment of corrosive liquids so if you wish to use hydrochloric acid to reduce your pH levels then a visit to your local hardware or pool shop is required.

pH Levels to shoot for – 7.2 to 7.4

Starting pH Level Per 10,000 Liters

7.6 to 7.8


7.8 to 8.0


8.0 to 8.4


8.4 and above


How do I add hydrochloric acid to my pool - After making sure that you have all of your protective equipment on, it’s best to dilute hydrochloric acid before adding it to your pool to make sure that there are no concentrated patches. To dilute hydrochloric acid, take a bucket of pool water (at least 10x the amount of acid that you plan to add to your pool) and add the acid to the bucket.

Note: ALWAYS add the acid TO the water and not the other way around.

Once the acid is added, mix the contents of the bucket thoroughly and pour at the DEEPEST part of your pool.

Filter / Pump Status – If your filter has a recirculate setting, it’s best to place it at that setting. Allow the pump to run for 24 hours to circulate the acid around the pool

How long can I swim after adding hydrochloric acid to my pool - If you’re adding a lot of acid to your pool (ie, adjusting pH from the 8.0 levels and above) make sure to let 24 hours pass and TEST THE WATER before getting into the pool to see if the water isn’t too acidic.

If you’re just doing small adjustments, you can re-test the water after two hours to see if the pH has dropped to the desired levels and if it has, you can take a swim then and there. If it needs further adjustment, add some more acid following the steps above and re-test in a couple of more hours before getting back in the pool.

Note: Always make sure that your pool pump is running and circulating the water when adding acid.

Sodium Bisulfate / pH Down Tablets

For those who do not want to be handling hydrochloric acid, sodium bisulfate (dry acid) can be used to lower the pool’s pH. pH down tablets can be added directly to the pool’s skimmers for it to be circulated into the pool directly and easily. They’re a little bit more expensive than hydrochloric acid, but they produce no fumes, there’s no risk for splashes and irritation, and best of all, it’s much more convenient to handle and store.

pH levels to shoot for - 7.2 to 7.4

How much should I add - Refer to the dosing information by the manufacturer on the packaging as each manufacturer has their own tablet size. But from experience, it usually just takes one or two tablets to lower the pH of a medium-sized pool.

Filter / Pump Status - Allow six hours for the water to fully circulate after adding pH down tablets. If your filter has a re-circulate setting then set it to recirculate to prevent damage to your filter elements. RE-TEST the water before swimming to check your pH levels.

How long can I swim after adding pH down tablets – Make sure to check your pH levels before swimming, but 6 hours should be enough time to wait after adding pH down tablets.

Calcium Up / Calcium Hardness

Calcium Up increases your pool’s calcium hardness levels. Water seeks to naturally balance its calcium levels, so if your water’s calcium hardness levels drop below the required levels, it will look for sources to supplement that need and the only place it can get that calcium is from your pool’s surfaces, grout, and cement, causing corrosion.

Calcium Hardness levels to shoot for – 200 to 400 PPM

How much Calcium Up to add - 100g of calcium up to raise the calcium hardness of the water by 10 PPM for every 10,000 liters.

How to add calcium up – For small amounts, you can directly add the calcium up to your pool’s skimmer boxes as it dissolves readily. If you need to add larger amounts, you can dissolve the calcium up in a bucket of pool water and broadcast it evenly around your pool.

Pump / Filter Status – Leave the pump running for at least one full cycle or 8 hours after adding calcium up to ensure that your pool’s calcium level is properly spread out.

How long can I swim after adding calcium up – You can take a swim 2 to 4 hours after adding calcium up, but it is generally recommended to swim only after your pool water has been completely circulated (up to 8 hours depending on your pool size and pump.

Calcium Down

Calcium down is the opposite of the previous chemical. Remember that water will look for its natural balance when it comes to calcium, when it has too much calcium, it will begin spitting it out and the result will be hard water stains or watermarks. Calcium down is made from Hydroxyethylidene Diphosphonic Acid Complex (A mouthful! But everyone knows it as Calcium down so you don’t have to worry about memorizing the name) which binds with the excess calcium hardness levels in your pool to bring it down to the optimal levels.

Calcium Hardness levels to shoot for – 200 to 400 PPM

How much calcium down to add – Refer to the instructions on the bottle as different brands will have different concentrations.

How to add calcium down to your pool – Dilute the solution in a bucket of pool water and broadcast evenly around the pool to maximize the effectivity of your calcium down solution.

Pump / Filter Status – Allow your pump to run for at least 8 hours after adding calcium down to your pool and ensure that your filter is actively filtering so that it will catch the calcium particles drawn out by the solution. You may need to clean or backwash your filter 24 hours after application.

How long after application of Calcium down can I swim – It’s advisable to wait for at least 8 hours before taking a swim.

Phosphate Remover and Algaecide

These two chemicals work in tandem to make sure that you won’t have to deal with green pool water in the future. Phosphate remover works by destroying phosphate in your pool water which serves as algae food and Algaecide kills algae spores and growth outright.

How much to add to your pool – Refer to the product label as each manufacturer has their own concentration levels and recommended dosage instructions.

How to add Phosphate Remover and Algaecide to your pool – broadcast the chemical evenly around the pool for maximum effectivity

Pump / Filter Status – As with any other pool chemical, allow the pump to run for at least 8 hours to ensure that the phosphate remover or algaecide is fully circulated around your pool.

How long after application of phosphate remover / algaecide can I swim – These chemicals have been proven safe (as long as you’re not part algae) and you can take a swim in your pool 20 minutes after application.

Clarifying Cubes

Clarifying Cubes, well, they clarify your pool water. They do this by binding with the microscopic particles in your pool allowing your filter to easily catch them. Clarifying Cubes take some time to use and are a longer-term solution, so if you’re looking for something to work really fast then move on to the next chemical down the list (flocculants). Clarifying cubes work for both sand and cartridge filters.

How much to add to your pool – One cube in your skimmer basket once a month, and you're good to go!

Pump / Filter Status – Use your filter and pump as your normally would as clarifiers take a long time to work.

How long after application can you swim – Immediately!


This is the ultimate treatment for cloudy pool water. If you’re in a hurry (having a pool party the next day) then flocculants are the way to go. Flocculants work by actively binding with particles in your pool so that they will be large enough to sink to the bottom of your pool and can be easily vacuumed out.

Important note: Flocculants are not advisable on cartridge filters as they can damage your filter cartridge elements.

How to apply flocculants to your pool

  • IMPORTANT – Set your filter setting to RECIRCULATE. If you’re using an old cartridge filter or your valve isn’t functioning as it should, take our your filter cartridge to avoid damaging it.
  • Raise your pool water to its maximum level as you will be vacuuming out a lot of water after the treatment.
  • Dilute the flocculant in a 5-gallon container with pool water and broadcast it evenly around your pool
  • Allow the pump to run for a few hours to fully circulate the flocculant around the pool.
  • Turn off your pool pump and allow to rest for 8-12 hours (or overnight)
  • Set your filter setting to “WASTE”
  • Vacuum the particles that have settled down on the bottom of your pool
  • Backwash your pool filter / return your filter cartridge


How long after applying flocculants can you swim – Do not swim in your pool while flocculant treatment is ongoing as the pool water needs to be undisturbed so that the flocculants can bind with the particles floating in and around your pool. Only swim after the vacuuming is done.


That’s it! That’s basically all of the pool chemicals you’ll ever need for your pool. There are others which we may have available on our online shop, but those are specialty chemicals that make life easier for pool owners but are not considered as “essential” in pool-man speak. To see our entire collection of pool chemicals, see Mr Pool Man’s Range of Pool Chemicals Available Online.

Need help testing your pool water? Head on down to Mr Pool Man's Ultimate guide to Testing your pool water for more information!

Products Featured on this Blog Post

Do you have any questions about this topic or the featured products? No worries, we're here to help! Drop us a question down below and we'll get back to you ASAP.

Happy swimming :)

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