We’ve all been there – your pool is looking a bit green and slimy, and you’re desperate to get it sparkling clean again. You head to the store and see those big jugs of bleach and think “Hey, bleach kills germs, right? Maybe I can use that to shock my pool and get it looking brand new!” But hold up – before you start pouring bleach willy-nilly into your pool, let’s look at whether using bleach for pool cleaning is a good idea.
What Is Bleach?
First, let’s define what we mean by “bleach.” The type of liquid bleach you can buy at the grocery store is a solution of sodium hypochlorite and water. This is different from other chlorine-based pool shock treatments which contain calcium hypochlorite.
Sodium hypochlorite is very effective at killing bacteria, viruses, and fungi. That’s why it’s used for disinfecting and sanitizing. However, it’s a powerful oxidizer that can be harsh on many surfaces if not diluted properly. Using too much or the wrong type of bleach could potentially damage your pool surfaces and equipment.
So Can I Use Bleach in My Pool or Not?
The short answer is: yes, you can use liquid bleach to sanitize and disinfect your pool, but only if you use it correctly and in the right concentrations. Simply dumping jugs of grocery store bleach straight into the pool water is never a good idea.
Using liquid bleach in your pool requires carefully calculating how much to add based on your pool’s volume and following very specific procedures. Even a small overdose of bleach can quickly raise chlorine levels to an unsafe range, causing issues like:
- Burning eyes, skin, and nasal passages
- Corrosion and etching of pool surfaces
- Damage to pool equipment like pumps and filters
- Excessive chloramine buildup leads to strong chemical odours
If you do decide to use bleach, you must buy an unscented liquid bleach that contains only sodium hypochlorite as the active ingredient – no extras like fragrance. You’ll also need a test kit to carefully monitor chlorine and pH levels both before and after adding the bleach.
Calculating Bleach for Your Pool
To calculate how much bleach to add to your pool, you’ll need to know:
- The pool’s volume in gallons
- The current free chlorine level
- The target free chlorine level you want to achieve
Most residential pools should maintain a free chlorine level between 1-3 ppm. To raise the level, use this formula:
Gallons to raise 1 ppm = Pool Volume (gallons) x 10%
Ounces of bleach to add = Gallons to raise 1 ppm x (Target ppm - Current ppm)For example, if you have a 20,000-gallon pool at 1 ppm currently and want to get it to 3 ppm:
Gallons to raise 1 ppm = 20,000 x 0.1 = 2,000
Ounces of bleach = 2,000 x (3 - 1) = 4,000 ounces or 31 gallons of bleachAs you can see, that’s a massive amount of bleach! Extreme care must be taken.
Pro Tip: Start with a very small dose, like 1-2 quarts of bleach for that 20,000-gallon pool. Run the pump for 24 hours, retest, and add more bleach if needed in small increments until your target level is reached.
Expert Opinion on Using Bleach to Clean Pools
We checked with pool maintenance professionals to get their take on using household bleach in pools. Keith Courter, a pool repair technician with over 15 years of experience, does not recommend it:
“I never advise using regular household bleach in a pool. There are pool-specific chlorine shock treatments made just for this purpose that are safer, easier to measure, and won’t cause as many water chemistry issues. Household bleach is really only for things like disinfecting surfaces, not raising and maintaining sanitizer levels in a large body of water.”
However, long-time pool service tech Dana Young says in an emergency bleach can work:
“Household bleach isn’t ideal for pools, but if you’re in a pinch and can’t get to the store for pool chlorine right away, you can use it very temporarily and carefully to get sanitizer levels up. Just be sure to aerate the pool really well afterwards to help burn off excess chloramines from the bleach.”
The Safer Alternatives to Household Bleach
If you don’t want to risk using household bleach on your pool, there are much better pool-specific shocking and sanitizing options available:
Calcium Hypochlorite (Cal-Hypo)
Cal-hypo is a granulated solid chlorine shock treatment. It raises chlorine levels quickly and doesn’t affect pH as much as bleach can. It’s easy to get the right concentration when following dosage instructions.
One of the most popular cal-hypo products is HTH Chlorine Pool Shock, which comes in 1 lb bags or buckets. The convenient pre-measured packets make it simple to get your chlorine boost.
Sodium Dichlor
Sodium dichlor chlorinates and stabilizes chlorine levels in one go. It’s less harsh than cal-hypo but still very effective. A great sodium dichlor option is Bioguard Kem-Tec 60 with 60% available chlorine.
Salt Chlorine Generators
For pools with a salt chlorine generator (SWG or salt cell), you’ll want to use tablets or granular salt specifically made for these systems. This allows the generator to efficiently make chlorine from salt without other additives getting in the way.
Green Blob Salt for Salt Cells is designed to work great with popular SWGs like Hayward Salt & Swim, Pentair IntelliChlor, and AquaRite systems.
Non-Chlorine Shocks
There are also non-chlorine oxidizing shock treatments like potassium peroxymonopersulfate that are gentler alternatives for sanitizing pools, especially if you have chlorine sensitivities.
SunPure 720860A Non-Chlorine Shock is a popular non-chlorine option that can be used as a periodic oxidizing shock without affecting chlorine levels.
The Best Way to Keep Your Pool Clean and Clear
While shocking your pool periodically is necessary for sanitization, the absolute best way to keep it sparkling clean is through consistent, small doses of chlorine or bromine along with regular brushing, vacuuming, skimming, and water testing.
Following a full and proper maintenance schedule is key to preventing issues like algae bloom that necessitate risky treatments in the first place. With a little effort each week, you can keep chlorine levels stable and your pool water looking beautiful all season.
Pro Tip: Use a premium two-in-one chlorine and algaecide product like Pool Essentials Chemical Feeder with Clearnex to easily maintain perfect chlorine and algae levels with minimal effort.
When in Doubt, Call a Pro
If you’re unsure about what chemicals to use, safety procedures, or how to get your pool water balanced correctly, don’t take chances – call a professional pool service for assistance. They have the experience and knowledge to analyze your pool’s situation and make sure it gets treated properly without any damage.
While using bleach to clean a pool can be done with extreme caution, in most cases there are easier and safer pool-grade chemicals to use. With some basic pool maintenance know-how, you can keep your pool crystal clear and avoid risky problems down the line. Your future (chlorine-balanced) self will thank you!
The Risks of Using Household Bleach in Pools
Let’s look at some of the major risks and downsides of relying on household bleach rather than proper pool chemicals:
Bleach is Unstabilized
Pool chlorine like cal-hypo or dichlor contains cyanuric acid to stabilize chlorine and prevent it from dissipating rapidly in sunlight. Household bleach has no stabilizer, so the chlorine gets burned off very quickly by UV rays. This makes it extremely inefficient for outdoor pools.
Highly pH Raising
Sodium hypochlorite solutions like bleach are very high in pH, usually around 13. Adding bleach directly can cause wild swings in pool pH into the alkaline danger zone where chlorine becomes ineffective.
Bleach Contains Additives
Many household bleaches contain added fragrances, colourants, and other ingredients that don’t belong in a pool and can cause cloudy water issues.
More Chloramine Formation
The sodium hypochlorite in bleach reacts much more readily with ammonia and nitrogen compounds to form potent chloramines that cause burning eyes, skin, and strong chemical odours.
For these reasons, it’s always better to use chlorine formulated specifically for pool use whenever possible.
Proper Pool Shock Procedures
If you do opt to use household bleach to raise chlorine levels, certain procedures must be followed:
- Test First – Test the pool water and calculate exactly how much bleach is needed to reach the desired free chlorine level based on the pool volume. Never just dump bleach in without measuring.
- Prep the Pool – Shock the pool during the evening or night to prevent chlorine from burning off too quickly from the sun. Remove any chlorine stabilizer first.
- Add Slowly – Pour the bleach in very slowly while the pump is running to allow for dispersal. Never dump it all in one area.
- Wait to Use – Don’t enter the pool for at least 8-12 hours after shocking and until chlorine levels have returned to normal range.
- Aerate Well – Run the pump continuously for 24+ hours to help burn off any chloramine odours or irritants.
Pro Tip: Buy a high-quality testing kit like the Taylor K-2005 DPD Test Kit for accurate chlorine, pH, and other readings during this process.
When to Use Non-Chlorine Treatments
While chlorine is king for sanitizing pools, there are situations where switching to non-chlorine oxidizing shock may be better:
- For chlorine-sensitive individuals
- To temporarily reduce combined chlorine/chloramines
- If an algae strain is resistant to chlorine
- To “double shock” after a heavy chlorine dose
Some popular non-chlorine pool oxidizers include:
- Potassium peroxymonopersulfate (potassium monopersulfate)
- Hydrogen peroxide
- Ozone generators
- Biguanides like PHMB
These can provide a powerful alternative way to bring pool chemistry back in balance when chlorine alone isn’t cutting it.
The Importance of Balanced Pool Chemistry
At the end of the day, keeping your pool sparkling clean relies just as much on maintaining proper overall water chemistry as it does on chlorine levels alone. Key factors like:
- pH range (7.2 – 7.8 is ideal)
- Total alkalinity
- Calcium hardness
- Stabilizer (cyanuric acid)
…all need to be continuously monitored and adjusted.
Using household bleach or other inappropriate chemicals can quickly throw off this delicate balance, leading to scaling, cloudy water, algae growth, and expensive problems down the road.
Pro Tip: Consider investing in a smart pool monitor like the iONIC PM5260 Inground Pool Monitor that continuously tracks all your pool chemistry levels and can automatically dispense chemicals as needed for the perfect balance.
The bottom line is that while you can use bleach in pools in an emergency, it’s not the ideal choice for routine chlorination and sanitation. Sticking with high-quality, pool-grade chlorine treatments while following best practices for maintenance is always the safest way to keep your pool clean, clear, and swimmable all season long.