You’re out of the regular chemicals you use to clean your hot tub. Is it ok to just use household bleach instead?
Clorox or bleach is OK to use in a hot tub providing it doesn’t have added colors or scents. Bleach is the same thing as liquid pool chlorine (sodium hypochlorite). The only difference is household bleach is around 6% strength, whereas pool chlorine is usually 12%.
Read further to understand when and how you should use bleach as a substitute.
The Difference Between Bleach and Clorox
Clorox and bleach are terms that are often used interchangeably, but are they the same thing? Bleach is sold under different brand names and Clorox happens to be one of them. Clorox is probably one of the most familiar brand names for bleach, but you can buy bleach without the Clorox name.
There is no difference in strength or chemical makeup when you buy bleach instead of Clorox. The difference in price is simply due to the brand name and its popularity.
Bleach Vs Other Hot Tub Chlorines
Bleach / Liquid Pool Chlorine
Liquid pool chlorine is a bleach that is sold in a stronger concentration than household cleaners. Liquid chlorine and bleach are also known as sodium hypochlorite.
Liquid Pool chlorine is usually around 12% in strength. Bleach or Clorox, around 6%.
Both household bleach and liquid pool chlorine are unstabilized, meaning they can break down when exposed to sunlight.
Liquid chlorine is an option for water treatment if the hot tub is indoors or in a covered area without much direct sun exposure.
Dichlor is another type of chlorine used in hot tubs. It typically comes in granular form. This chlorine has a stabilizer (cyanuric acid or CYA) already added to it. That makes it more suitable for spas that receive sunlight because it keeps the chlorine from burning off as quickly. It’s probably the most common chlorine product for hot tubs.
Trichlor is sometimes used in spas, but not as often as dichlor. It comes in a granular form. Like dichlor, it also has CYA already added to it. But it has a much higher acidity level than dichlor and can cause erosion. If you use this form of chlorine, you’ll have to keep a closer eye on the pH levels to keep the water balanced.
Calcium hypochlorite is most commonly referred to as shock. It dissolves quickly and is fast-acting in the water. It does have a higher pH level, so you may have to adjust other chemicals when using calcium hypochlorite.
Because of the calcium, it can leave deposits on the heater or other spa parts. You might also see a ring around the top of the water line if you use this in the hot tub. It’s not usually recommended for daily hot tub sanitation.
Related Reading: How to Shock a Hot Tub
Why Would You Use Bleach in a Hot Tub?
- Easier to find
- Longer shelf life than pool liquid chlorine
- Doesn’t add stabilizer (cyanuric acid/CYA)
Easier to Find & Cheaper
Household bleach can be easier to find than chlorine spa products. So if you’re out of chlorine, chances are you have some bleach on-hand to substitute if needed. It’s sold at regular stores and won’t require a trip to a pool store to purchase.
Liquid bleach is also cheaper to purchase than chemicals manufactured for pools.
Longer Shelf Life
Bleach is also cheap and because it has a lower concentration of chlorine in it, the shelf life is longer. Liquid pool chlorine can lose 50% of its potency in just a few weeks if stored in hot conditions.
The same is not true for bleach or Clorox.
Related Reading: How Long Does Pool Chlorine Last For (Shelf Life)?
Doesn’t Add Stabilizer
Using stabilized chlorine in a hot tub adds a chemical called Cyanuric Acid. It’s used to prevent chlorine from degrading in the sunlight.
The problem is, if you use a stabilized chlorine like Dichlor or Trichlor as your regular sanitizer, stabilizer levels can build up very quickly in a hot tub or spa. The issue with this is that chlorine becomes far less effective with high levels of stabilizer.
Using unstabilized chlorine from time to time, like bleach, can prevent this.
Why You Wouldn’t Use Bleach in a Hot Tub
- Over chlorination
- No stabilizer
- Shorter shelf life than granular chlorine
- Not as safe to use
Over Chlorination & No Stabilizer
There is no stabilizer in liquid bleach. If you have an outdoor hot tub, the stabilizer is something you’ll need to prevent chlorine degradation.
And additionally, if there is no stabilizer in the water, using liquid bleach can in fact lead to over-chlorination. Over-chlorination is not only bad for swimmers, but it’s also bad for the hot tub components too.
Over-chlorination can cause dry, itchy skin and can impact the pH of the water. Remember that chlorine in the liquid form is unstabilized and could require you to add CYA to keep the water balanced.
Over chlorination of the water can end up harming the hot tub cover, break down elastics sooner, and possibly void your hot tub warranty.
Short Shelf Life than Granular Chlorine
Granular chlorine, which is often recommended for hot tubs, keeps for much longer than any form of liquid chlorine. Liquid chlorine and bleach start degrading, even when not opened, as soon as they are manufactured.
The shelf life might be as short as a few weeks. Granular chlorine on the other hand can keep for years, as long as it’s kept away from moisture.
Not as Safe to Use
Spills from liquid bleach can end up leaving stains on your hot tub or cover. If you get in the water before chemicals are completely mixed, you might also have staining on bathing suits or clothing.
There are also no instructions on the packaging for how much to use in your hot tub, so you will be guessing at the amount needed to provide the proper sanitation.
Should You Use Bleach in a Hot Tub?
If you would like to use bleach in your hot tub, here are a few tips.
- Make sure it’s unscented
- Use only the “regular” bleach varieties
- Be prepared to add some CYA (cyanuric acid) to the water in addition to the bleach for longer-lasting water treatment
- Have water test strips available to make sure the pH levels don’t rise too much
- Measure carefully so you don’t over-chlorinate
Adding Cyanuric Acid to Water
If you’re using liquid bleach, you might want to consider adding some to your water. This is less important if the hot tub is covered and out of direct sunlight since the light breaks down the chlorine faster, but you can still add it to a covered spa if desired.
But there is a school of thought that says a little bit of CYA will help prevent over-chlorination.
The recommended level of stabilizer for a spa or hot tub is 30-50 ppm. You’ll need test strips to accurately measure the amount of CYA in the water so you know how much you need to add to reach the desired range.
Be careful that you don’t add too much CYA to the water! When the CYA levels get too high, they basically void any of the sanitation properties of your bleach. The only way to lower the CYA levels is to drain some of the water from the hot tub and add clean, untreated water back into the hot tub to dilute the concentration.
Related Reading: Hot Tub Cyanuric Acid (Stabilizer) High | How to Lower
How to Use Bleach in Your Hot Tub
- Get a test strip kit to check the chemical level present in your hot tub BEFORE adding any bleach
- Calculate how much bleach you need to add based on your current chemical levels. Adding 1/2 tsp of regular bleach will increase the chlorine level of 100 gallons of water by 1 ppm.
- Chemicals will mix faster if the jets are running to circulate the water.
- Recheck chemical levels regularly (every 2-3 days) to make sure they are correct.
Does Bleach Void a Hot Tub Warranty?
In some cases, using bleach can void your warranty. Because liquid bleach can over-chlorinate the water, which is harsher on hot tub equipment, it is not recommended by most manufacturers.
If you’re unsure, it’s a good idea to check your warranty information before adding any bleach to your hot tub.
Cleaning Hot Tubs with Bleach
If you want to use liquid bleach to sanitize an empty hot tub, follow these steps.
- Drain the hot tub completely
- Use a diluted bleach mix according to sanitizing directions on the package
- Wipe down all surfaces and allow them to air dry before refilling the hot tub with water.
- Do not mix bleach with any other chemicals or types of chlorine. You don’t want to create chemical reactions that could be harmful to you or to the hot tub itself.