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Dichlor/bleach Method In A Nutshell


Nitro
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18 hours ago, nmiller0113 said:

Quick question, is this the Clorox that @Nitro was referring to?

Basically yes. It is a 6% sodium hypochlorite with added water clarifiers to prevent dirt from depositing back on clothes in the laundry. However, these very same chemicals are also used as water clarifiers in pools and spas so they will have no negative impact. House brand bleach is normally cheaper then Clorox and just as effective. I buy bleach at Walmart or the grocery store and buy their brand. However, because of Covid-19 the number of bottles of bleach you can buy is often limited so pool chlorine at 10% or 12.5% might be a more viable option, depending on how much you need. For a spa a one gallon jug will last a long time and you can also use it in the laundry or around the house. Just make sure it's a disinfecting bleach with no scents, thickeners, soaps, or other additives (except Poly(Diallyldimethylammonium Chloride) or Polycrylic acid,which are the clarifiers. Besides sodium hypochlorite and water  you will also often find sodium chloride, sodium hydroxide, sodium carbonate, and/or sodium chlorate listed in the ingredients. These are all normal and are either byproducts of manufacture or storage of the product and are nothing to worry about.

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  • 3 months later...
  • 1 month later...
27 minutes ago, Dancemore said:

Does this method (for hot tubs) also work with Trichlor?  (Trichlor-then-bleach instead of dichlor-then-bleach?)

We have a jug of trichlor tabs left we'd like to use up.  Thank you!

Some more context: Our city water comes in with a pH of 8+.  i’m aware of Chemgeek’s post about Trichlor dissolving fast, lowering pH, and (a plus for us), adding less CYA than dichlor.  The tub is old and not under warranty.  We’ve had pretty low pH after a year though, yet crisp water just using the stabilized trichloro-s-triazinetrione.  So we’ve used Trichlor but never switched over to bleach and I thought of trying that to see if pH will not pull down and wondered if that’s a stupid idea.  Thank you for all the solid advice on this forum!

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11 hours ago, Dancemore said:

Our city water comes in with a pH of 8+

What is the total alkalinity of your fill water? IF you are going to run trichllr then your TA should be in the range of 100 to 120 PPM and, because of the aeration from the jets you will need to monitor both pH and TA closely. Once you switch over to bleach  you will need to lower the TA to around 50 to 70 ppm.

If your initial TA is higher than about 150 ( IMHO is still too high for a spa, IMHO, even when running trichlor) you will need to lower the TA at filling or you will find that your pH will rise too quickly and you will be constantly fighting it.

https://www.poolspaforum.com/forum/index.php?/topic/52522-some-truths-about-ph-and-ta/

 

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On 6/19/2021 at 6:00 AM, waterbear said:

What is the total alkalinity of your fill water? IF you are going to run trichllr then your TA should be in the range of 100 to 120 PPM and, because of the aeration from the jets you will need to monitor both pH and TA closely. Once you switch over to bleach  you will need to lower the TA to around 50 to 70 ppm.

If your initial TA is higher than about 150 ( IMHO is still too high for a spa, IMHO, even when running trichlor) you will need to lower the TA at filling or you will find that your pH will rise too quickly and you will be constantly fighting it.

https://www.poolspaforum.com/forum/index.php?/topic/52522-some-truths-about-ph-and-ta/

 

Our fill water has a TA of 75 with that pH of 8+.  Ok, thank you, I raised it to 100 PPM and will try to keep it there until switching to bleach

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  • 4 months later...
On 1/4/2021 at 11:45 AM, waterbear said:

 

Basically yes. It is a 6% sodium hypochlorite with added water clarifiers to prevent dirt from depositing back on clothes in the laundry. However, these very same chemicals are also used as water clarifiers in pools and spas so they will have no negative impact. House brand bleach is normally cheaper then Clorox and just as effective. I buy bleach at Walmart or the grocery store and buy their brand. However, because of Covid-19 the number of bottles of bleach you can buy is often limited so pool chlorine at 10% or 12.5% might be a more viable option, depending on how much you need. For a spa a one gallon jug will last a long time and you can also use it in the laundry or around the house. Just make sure it's a disinfecting bleach with no scents, thickeners, soaps, or other additives (except Poly(Diallyldimethylammonium Chloride) or Polycrylic acid,which are the clarifiers. Besides sodium hypochlorite and water  you will also often find sodium chloride, sodium hydroxide, sodium carbonate, and/or sodium chlorate listed in the ingredients. These are all normal and are either byproducts of manufacture or storage of the product and are nothing to worry about.

@waterbear first of all...thank you again for the previous advice you provided. My hot tub has been amazing! I was looking to get more bleach and the previous one I had been purchasing is no longer available. You had mentioned that you bought the cheaper brand so I was wondering if you had a link to that so I could order some? Thank you again and I hope all is well!

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55 minutes ago, nmiller0113 said:

@waterbear I hate to bother, just wondering if you saw my question above. Thank you again for your help!

Any brand of (either germicidal or laundry) chlorine bleach without scents,  thickeners, or detergents that is 5.25%, 6%, or 8.25% OR liquid pool chlorine that is 10% or 12.5% is fine. It does not to be Clorox brand.  House brands from the grocer or big box store are fine as long as their are plain unscented unthickened chlorine bleach or liquid pool chlorine in the strengths listed.

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On 11/10/2021 at 7:47 PM, waterbear said:

Any brand of (either germicidal or laundry) chlorine bleach without scents,  thickeners, or detergents that is 5.25%, 6%, or 8.25% OR liquid pool chlorine that is 10% or 12.5% is fine. It does not to be Clorox brand.  House brands from the grocer or big box store are fine as long as their are plain unscented unthickened chlorine bleach or liquid pool chlorine in the strengths listed.

As usual @waterbear, you’re a great help! I ended up finding one that’s germicidal and generic from Lowe’s 121-fl oz Germicidal Bleach https://www.lowes.com/pd/Style-Selections-121-fl-oz-Germicidal-Bleach/50064623

it has no thickeners or detergents that I can find, and it’s unscented. The side says:

Sodium Hypochlorite 6%
Other Ingredients 94%

Available Chlorine 6%

i think that’s exactly what I need. Thank you again and Happy Thanksgiving!

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Laundry bleach from such places as Walmart or grocery stores is also fine to use as long as it's 5%, 6.25% or 8.25%  sodium hypochlorite and it is not scented or thickened. I usually buy bleach at Walmart or my local grocery. In fact, Lowes, Home Depot and my local grocery all stock 10% pool chlorine in my area also.

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  • 3 months later...

Switched to the bleach method, and have really liked the ease of use so far.

Just got the water tested at the pool store: Free Chlorine 0.9ppm, Combined Chlorine 2.2ppm.

Would it make sense to shock with bleach up to 22ppm FC?

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only if there is no CYA in the water. Post a full set of test results and how they were done (strips, liquid reagents, strips in a reader, liquid or tablet reagents in a reader, dealer testing (and was it liquid reagents or was it discs or strips in a reader) and we can take it from there

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These are the results of testing done by dealer:

Free Chlorine: 0.89ppm

Total Chlorine: 3.12ppm

Combined Chlorine: 2.23ppm

pH 8.2

Alkalinity 122ppm

Adjusted Alkalinity 98ppm

Calcium Hardness 158ppm

CYA 79ppm

 

I have balanced the pH down to 7.4 and the alkalinity has come down with it to about 50ppm. (Tested with Strips)

Water has been clear throughout, but I think I must not have added enough bleach after every use. The Original Clorox here in Canada does not state the %Chlorine on the bottle, which is not helpful. Thank you for your thoughts!

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1 hour ago, D7m said:

These are the results of testing done by dealer

are they using strips in a reader, disc in a reader, or liquid reagents or tablets in a reader?

1 hour ago, D7m said:

CYA 79ppm

This is the red flag. With a CYA of 79 you need to maintain the FC in the 6 to 12 ppm range for normal chlorination with a target of about 9 ppm FC  and shock to about 32 ppm to get rid of the combined chloramines and other oxidation byproducts. (FC should be about 8% to 15% of the CYA level, with a target range of 11% to 12% of the CYA. Shock level is about 40% of the CYA level)

(Thanks to Chem Geek for determining these levels based on the work of Ben Powell from PoolForum)

My suggestion is to drain about about 2/3 of your water and replace it, rebalance, retest , and use the above percentages to determine where to maintain your FC and shock levels based on the CYA level and DO NOT USE A STABILIZED CHLORINE which will add more CYA (Dichlor adds 9 ppm CYA for every 10 ppm FC it adds). Use only unstabilized chlorine (bleach-sodium hypochlorite or lithium hypochlorite a fast dissolving unstabilized chlorine often sold as lithium shock, it's expensive)

When you do a full drain and refill use dichlor unti the CYA is about 30 ppm and then switch to bleach.

2 hours ago, D7m said:

The Original Clorox here in Canada does not state the %Chlorine on the bottle, which is not helpful.

Yeah, they say it's a proprietary secret. However the SDS for original lists it as between 3% - 7 % and the concentrated as between 4% - 9% which leads me to believe they are most likely the same as their US counterparts at 5.25% and 6 or possibly 6% and 7.5%. You can verify this by using the information in the link below and adding enough bleach to produce the values in the link based on the volume of water in YOUR tub and testing about 20 minutes after adding the bleach. For example if you have a 300 gal. tub you would need to add 3 tablespoons bleach to achieve the FC rise shown for each strength of bleach. You should then be able to determine the strength of your bleach,

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Thank you kindly! I'm sorry, I'm not sure what method the dealer used.

I will lower the CYA by draining/refilling partially and will go from there.

Earlier in this thread I had read that shocking is not required when using the bleach method. Could you elaborate on that?

Thank you once again for all the helpful info!

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  • 1 month later...

Newbie here....I recently switched to a salt generator for the tub after loving the experience I have with salt in the big pool.

The first fill went ok for a while but started having issues a few weeks in. Minimal bather loads.  Couldn't get chlorine levels high enough. TDS climbed to around 1800. Important? Now doing a refill. Is there a proper order to follow for balancing the new water? Is CYA important with salt and how do I adjust it? Dichlor shocks? Do I supplement the salt with dichlor or bleach? Any tips on keeping the balance. I am using the ControlOMatic SmarterSpa salt generator. It senses low chlorine and comes on automatically. I searched for a salt sticky, sorry for all the q's, and thanks in advance for your answers! 

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  • 2 months later...

So liquid pool chlorine at 10% sodium hypochlorite is literally the same as household bleach, just a bit stronger and without added stabilizers that dichlor and others add? I've been struggling to get CYA levels down after years of putting "whatever" pool chlorine in my spa so I'm going to do a flush and fill and start over using the method on page 1...

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There are 2 forms of stabilized chlorine, trichlor and dichlor. Trichlor is very acidic and therefore not recommended for spas. For every 10 ppm of free chlorine (FC) added trichlor adds 6 ppm of CYA. Dichlor is net acidic (acidic on application and had an acidic reaction when it sanitizes) and it is commonly used in hot tubs. For every 10 ppm FC added it add 9 ppm CYA.

There are 3 unstabilized chlorine sources, calcium hypochlorite (cal hypo), lithium hypochlorite, and sodium hypochlorite.

Calcium hypoclorite is a slow dissolving powder that is basically net neutral (alkaline on addition and acidic reaction when it sanitizes) and it adds 7 ppm calcium hardness for every 10 ppm FC added.

Lithium hypochlorite is a fast dissolving power that is net neutral also. It's main drawback is that it is the most epen$ive form of chlorine.

Sodium hypochlorite is also a net neutral chlorine source. It is a liquid that commonly available in 10% AND 12.5% strength as liquid pool chlorine or liquid shock. It is also readily available as liquid chlorine laundry bleach (you want the plain, unscented, unthickened type without added detergents or additives). It is commonly available in 5.25% (regular) and 6% (ultra). It is also sometimes sold in 8.25% and 3%. The 3% is often sold at dollar stores and is usually more expensive to use because of the amount needed to reach a specific FC level. Chemically, laundry bleach and pool chlorine are EXACTLY the same except for the strength (just as alkalinity increaser and baking soda are exactly the same since both are sodium bicarbonate AKA sodium hydrogen carbonate).

Sometimes Brand Name plain, unscented, unthickened laundry bleach will contain some additional chemicals such as polydiallyldimethylammounium chloride ( Polyquaternium-6) and Sodium polyacrylate to prevent dirt from redepositing on clothes in the wash. These particular additives with not have a negative impact and, in fact, are also the main ingredients in many water clarifiers used in pools and spas.

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On 6/1/2022 at 9:14 AM, waterbear said:

There are 2 forms of stabilized chlorine, trichlor and dichlor. Trichlor is very acidic and therefore not recommended for spas. For every 10 ppm of free chlorine (FC) added trichlor adds 6 ppm of CYA. Dichlor is net acidic (acidic on application and had an acidic reaction when it sanitizes) and it is commonly used in hot tubs. For every 10 ppm FC added it add 9 ppm CYA.

There are 3 unstabilized chlorine sources, calcium hypochlorite (cal hypo), lithium hypochlorite, and sodium hypochlorite.

Calcium hypoclorite is a slow dissolving powder that is basically net neutral (alkaline on addition and acidic reaction when it sanitizes) and it adds 7 ppm calcium hardness for every 10 ppm FC added.

Lithium hypochlorite is a fast dissolving power that is net neutral also. It's main drawback is that it is the most epen$ive form of chlorine.

Sodium hypochlorite is also a net neutral chlorine source. It is a liquid that commonly available in 10% AND 12.5% strength as liquid pool chlorine or liquid shock. It is also readily available as liquid chlorine laundry bleach (you want the plain, unscented, unthickened type without added detergents or additives). It is commonly available in 5.25% (regular) and 6% (ultra). It is also sometimes sold in 8.25% and 3%. The 3% is often sold at dollar stores and is usually more expensive to use because of the amount needed to reach a specific FC level. Chemically, laundry bleach and pool chlorine are EXACTLY the same except for the strength (just as alkalinity increaser and baking soda are exactly the same since both are sodium bicarbonate AKA sodium hydrogen carbonate).

Sometimes Brand Name plain, unscented, unthickened laundry bleach will contain some additional chemicals such as polydiallyldimethylammounium chloride ( Polyquaternium-6) and Sodium polyacrylate to prevent dirt from redepositing on clothes in the wash. These particular additives with not have a negative impact and, in fact, are also the main ingredients in many water clarifiers used in pools and spas.

Thank you, since our spa never sees any direct sunlight (large umbrella covers it) and only even indirect light when used, maybe 30 min to 1 hr a day I will be using the liquid pool chlorine from now on, just very occasionally using up the dichlor powder to keep a little CYA in there. I can get 10% pool chlorine for the same price as even generic plain 7.5% bleach, so it will be very economical to keep up that way, just a little splash of it after every soak in our little 210 gallon tub. Thanks for clarifying!

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Even if it gets very little direct sunlight it's still a good idea to have about 30 ppm CYA since it acts as a "buffer" for the chlorine, making it less agressive on swimsuits and people.

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