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Chlorine Reading Zero After 24 Hrs


ZestyTub23

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We just recently got our hot tub.

Need alot of help to get this water balanced.

I have added stain control to the tub with the first water fill.

Since then I have added a cap full of BOOM (sodium dichloro-s- Triazinetrione) after each use. Which right now is almost every day.

I have used SWAT one package (40g) per week.

The tub has an ozonator.

I have a test kit TF-100 and test the water every day for Chlorine and pH.

What I don't understand, after I put the BOOM in the tub and after 20mins take a reading there is chlorine. After about 24 hrs, without anyone going into the tub the Chlorine reading is zero using the K-1000 taylor kit. Then I try to test the chlorine using the TF-100 kit and when I add R-0870 (DPD powder) to 10 ml of water it doesn't turn pink. It stays clear.

I also tried adding 6oz of Clorox instead of BOOM and I get the same result.

The water looks clear and right now it does have a bleach smell to it.

I have no idea what to do next.

Please Help

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With a brand new tub there can be a lot of leftover chemicals as well as biofilms developed from wet-testing of the tub. This can all create a rather large chlorine demand in a new tub. You should decontaminate the tub, either using Spa System Flush or doing superchlorination. See some of the links in the Dichlor/bleach Method In a Nutshell.

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With a brand new tub there can be a lot of leftover chemicals as well as biofilms developed from wet-testing of the tub. This can all create a rather large chlorine demand in a new tub. You should decontaminate the tub, either using Spa System Flush or doing superchlorination. See some of the links in the Dichlor/bleach Method In a Nutshell.

Thanks for your help, I'll get working on this right away.

If I still have trouble, do you mind if I let you know what I did and give you the test results?

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Thanks for your help, I'll get working on this right away.

If I still have trouble, do you mind if I let you know what I did and give you the test results?

Of course. That's what we're here for.

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The pH reading was at 8.2 so I decided to add 120ml of reducer and 60g BOOM then aerated 20 mins.

I just wanted to get that chlorine in there since it was always reading zero.

After 20 mins. the reading (10am) where FC=15,CC=2,pH=7.0,T/A= 200, CYA = 100 and CH= 180

To get T/A down, I tried to aerated for another 20 mins. Also, only one person had used the hot tub since adding chemical to the tub.

Now the reading(11pm) are FC = 11, CC=1, pH=7.2, T/A=140 and CYA =100

The T/A is still high, is there anything else I can do besides aerating to lower T/A?

I was thinking my next step is to keep aerating, add bleach after the next usage instead of BOOM so that CYA doesn't go higher. Does that sound okay?

Also, why is that CYA so high? Is there any way to lower it beside a full water change?

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The T/A is still high, is there anything else I can do besides aerating to lower T/A?

Aerating does not lower TA, the addition of acid lowers TA. Aerating raises pH without raising TA. SO....

To lower TA add enough acid to drop your pH to 7.0-7.2 and begin aeration. When the pH raises to 7.4 to 7.6 test the TA.

IF it is still to high lower the pH and aerate again.

Repeat until TA is where you want it. As the TA drops the pH and TA WILL move down with less and less acid so an acid demand test is most useful here (but the TF-100 does not include this test, which is why the Taylor k-2006 is a better kit, IMHO).

If your starting TA is high then it might not seem that the TA is moving at first but keep at it and you will see it begin to drop.

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Also, having a CYA at 100, you should just drain and refill the tub. High CYA means keeping higher chlorine levels because chlorine becomes less effective the higher your CYA levels are. 30-50 is what is needed for CYA. Since you need to drain anyway, i would suggest a decontamination process. Start over and see if your readings are better.

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Also, having a CYA at 100, you should just drain and refill the tub. High CYA means keeping higher chlorine levels because chlorine becomes less effective the higher your CYA levels are. 30-50 is what is needed for CYA. Since you need to drain anyway, i would suggest a decontamination process. Start over and see if your readings are better.

I agree. You are using dichlor I assume. Only use it long enough to get the CYA to 20-30 ppm then switch to bleach and you won't have to worry about over stabilizing (too high CYA).

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I was hoping there was another solution. Before I begin the joyful experience of draining and refilling the tub in freezing weather, does anyone have any tips to make this process easier?

So basically, this BOOM product brought the CYA up too high, I need to switch to bleach sooner. I am surprised how quickly it got up there. The tub was filled on Dec. 17th.

I am guessing this is the reason the chlorine was dropping to zero quickly.

I have a few more questions:

Is there a difference between he bleach or regular bleach?

When putting different chemicals in the tub is there any combination that shouldn't be put in together? What is okay to put in together?

Also, when testing for T/A the kit says the colour will change from green to red. When I count the number of drops there is a point when the solution goes clear. Then the next drop will make the solution slightly pink and with each additional drop the solution will have a darker pink colour (not red). At which point do you stop counting? Is it the drop right after it went clear?

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I was hoping there was another solution. Before I begin the joyful experience of draining and refilling the tub in freezing weather, does anyone have any tips to make this process easier?

So basically, this BOOM product brought the CYA up too high, I need to switch to bleach sooner. I am surprised how quickly it got up there. The tub was filled on Dec. 17th.

I am guessing this is the reason the chlorine was dropping to zero quickly.

For every 1 ppm FC added by dichlor it will add .9 ppm CYA. Almost a 1 to 1 ratio!

I have a few more questions:

Is there a difference between he bleach or regular bleach?

Yes, HE bleach is NOT a disinfectant nor are scented or specialty bleaches. You want plain, unscented regular or ultra bleach. Period.

When putting different chemicals in the tub is there any combination that shouldn't be put in together? What is okay to put in together?

If you wait a few minutes in between with the circulation going there is no problem. However, when making adjustments get one parameter in line before trying to adjust something else. For exampe, NEVER try and adjust pH when the FC level is above about 10 ppm because the high sanitizer levels chemically interferes with the pH test (and others too) and causes it to read high when it is not.

Also, when testing for T/A the kit says the colour will change from green to red. When I count the number of drops there is a point when the solution goes clear. Then the next drop will make the solution slightly pink and with each additional drop the solution will have a darker pink colour (not red). At which point do you stop counting? Is it the drop right after it went clear?

For all titration (drop counting) tests you want to keep adding drops until the addition of one more drop does not produce further color change and then you do not count that last drop. For exampe, with the TA test you add 5 drops and the color stays green, on drop 6 it gets sort of grey, stays grey on drop 7, turns pinkish on drop 8, gets brighter on drop 9 and produces no further color change on drop 10. Don't count that last drop. It took 9 drops to change from green to red and (with a 25 ml sample) this would be 90 ppm TA.

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I was hoping there was another solution. Before I begin the joyful experience of draining and refilling the tub in freezing weather, does anyone have any tips to make this process easier?

So basically, this BOOM product brought the CYA up too high, I need to switch to bleach sooner. I am surprised how quickly it got up there. The tub was filled on Dec. 17th.

I am guessing this is the reason the chlorine was dropping to zero quickly.

For every 1 ppm FC added by dichlor it will add .9 ppm CYA. Almost a 1 to 1 ratio!

I have a few more questions:

Is there a difference between he bleach or regular bleach?

Yes, HE bleach is NOT a disinfectant nor are scented or specialty bleaches. You want plain, unscented regular or ultra bleach. Period.

When putting different chemicals in the tub is there any combination that shouldn't be put in together? What is okay to put in together?

If you wait a few minutes in between with the circulation going there is no problem. However, when making adjustments get one parameter in line before trying to adjust something else. For exampe, NEVER try and adjust pH when the FC level is above about 10 ppm because the high sanitizer levels chemically interferes with the pH test (and others too) and causes it to read high when it is not.

Also, when testing for T/A the kit says the colour will change from green to red. When I count the number of drops there is a point when the solution goes clear. Then the next drop will make the solution slightly pink and with each additional drop the solution will have a darker pink colour (not red). At which point do you stop counting? Is it the drop right after it went clear?

For all titration (drop counting) tests you want to keep adding drops until the addition of one more drop does not produce further color change and then you do not count that last drop. For exampe, with the TA test you add 5 drops and the color stays green, on drop 6 it gets sort of grey, stays grey on drop 7, turns pinkish on drop 8, gets brighter on drop 9 and produces no further color change on drop 10. Don't count that last drop. It took 9 drops to change from green to red and (with a 25 ml sample) this would be 90 ppm TA.

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Thanks for your help. I am getting more information here than the place I bought the hot tub.

Does anyone know where I can get the Spa System Flush in Canada?

Also, the one month supply of chemicals from the place I got the hot tub was from

www.shuswaphottubs.com/user/image/spaguide.pdf

does anyone know anything about these products?

Should I put the stain control in which it says it emilinates and controls iron, copper and managanese on the next hot tub fill?

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Try Super Spa Supplies though its $35 Canadian.

You can see the pesticide registration at Health Canada for Sani-Marc. For some of these products, I'm guessing, but you don't need most of them. You would only need to add the stain control if you've got metal ions in your water, say from being well water. If you are using water from a municipal water supply, then look at a water report -- if it doesn't list iron or copper at levels of 0.2 ppm or higher, then don't bother using the metal sequestrant.

Spa Brom are just bromine tablets (BCDMH).

Spa active #1 is probably sodium bromide.

Spa active #2 is probably an oxidizer such as non-chlorine shock (MPS) or possibly Dichlor.

Spa sani-brom is faster dissolving bromine -- not sure in what form.

Spa alkalinity is probably just baking soda (sodium bicarbonate).

Spa calcium is probably just calcium chloride as found in de-icers such as Dowflake, Peladow and Tetra.

Spa plus sounds like sodium carbonate or perhaps lye already in water.

Spa minus sounds like sodium bisulfate or muriatic acid already diluted in water.

Spa jazz might be bromates.

Spa stain control is a metal sequestrant and scale inhibitor.

Spa clarifier is probably a polymeric clarifier.

Spa anti foam is a defoamer chemical (many different possible kinds).

Spa zyme are enzymes.

Spa protection might be phosphates as a corrosion inhibitor.

Spa drain is probably sodium thiosulfate or some other halogen neutralizer.

Spa tab is just Trichlor tabs.

Spa boom is just Dichlor granules/powder.

Spa energy is just lithium hypochlorite.

Spa max is Dichlor in tablet form.

Spa S.W.A.T. may be a polymeric clarifier (not sure what they mean by "accelerator").

Spa contact is a cartridge cleaner so possibly surfactants or maybe TSP.

Spa cal pro is a scale remover so probably a combination of acid and metal sequestrant.

Spa slip is a standard surface cleaner.

Spa bright is a cleaner for covers.

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Wow! thanks for all this information it was more than I could have ever expected. This forum and you guys are great.

Thanks again for your help in my quest for a perfecting my hot tub water.

Please have patience as I am sure I will have more questions.

/quote]

This is what we have done so far. We decided to wait until we get that SPA System Flush and 0 degree weather before doing a full hot tub water change.

So we took out half the water and replaced with fresh water. We cleaned out the filters. We let the temperature get back to 100 degrees. Took all our readings which were:

t/A = 90, pH - 8.2, CH=130, CYA = 35, FC=1, CC=1

We added 60ml of SPA minus from Sani-Marc. Took another pH reading after 20 mins. of aerating. It was pH=7.8.

Then we added 1 cup of bleach to try to get the FC=10ppm. The pool calculator said to add 350ml but we went a bit lower just in case.

After aerating for 20 mins. we noticed it was getting a bit foamy. Not sure why? We took our next chlorine reading it was FC=20, CC=2. I guess we should have added 1/2 cup of bleach instead.

Hopefully, we are doing this correctly?

Once I get the water perfect, my next task is to try to figure out why my 10 year old is getting a face rash. I know when she goes in swimming pools her eyes are sensitive and needs to wear goggles. I also find she is feeling faint afterwards so we lowered the temperature. Basically I have not allowed her to go into the tub and I put cortisone cream on her face until I figure this out.

So we will measure the FC after 24 hrs without anyone going in the tub and see what happens.

After 24 hrs the FC was 2.5 and CC=2, so chlorine demand is still high. Any suggestions on what to do next?

Also, I noted from other posts that 5oz of 6% bleach per person per hour of use for 350 gallons. So for 2044L tub that would be 7.7oz of bleach per person per hour, is my math correct?

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your combined chlorine not changing has me a bit baffled. your goal is 0 for combined chlorine, or as close as possible. sHOCKING THE TUB THE WAY YOU HAVE SHOULD BE CHANGING THIS SPECIALLY SINCE THE cya IS NOW AT 35. HAVE YOU CLEANED THE FILTERS AT ALL?

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your combined chlorine not changing has me a bit baffled. your goal is 0 for combined chlorine, or as close as possible. sHOCKING THE TUB THE WAY YOU HAVE SHOULD BE CHANGING THIS SPECIALLY SINCE THE cya IS NOW AT 35. HAVE YOU CLEANED THE FILTERS AT ALL?

Hello,

I cleaned the filters with water only. I still need to buy something to clean the outter filter. I have the Sundance Optima 880 which has two microclean filters, one is pleated on the outside and the other fits inside it has a smooth surface. The manual says only to ligthly clean the inner one with water only.

Right now, I am puzzled by the high chlorine demand. I am hoping once we completely drain and refill the tub this problem will go away. I believe I got all the other readings under control.

Another thing I was going to do some reading on was in the SPA manual it says: never add chlorine tablets (trichlor) or acid to your hot tub for any reason. These chemicals may damage components within your hot tub, burn or irritate your skin, create a rash, and void the manufacturer warranty.

where is Trichlor found? I am guessing with the acid it must be diluted first.

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your combined chlorine not changing has me a bit baffled. your goal is 0 for combined chlorine, or as close as possible. sHOCKING THE TUB THE WAY YOU HAVE SHOULD BE CHANGING THIS SPECIALLY SINCE THE cya IS NOW AT 35. HAVE YOU CLEANED THE FILTERS AT ALL?

Hello,

I cleaned the filters with water only. I still need to buy something to clean the outter filter. I have the Sundance Optima 880 which has two microclean filters, one is pleated on the outside and the other fits inside it has a smooth surface. The manual says only to ligthly clean the inner one with water only.

Right now, I am puzzled by the high chlorine demand. I am hoping once we completely drain and refill the tub this problem will go away. I believe I got all the other readings under control.

Another thing I was going to do some reading on was in the SPA manual it says: never add chlorine tablets (trichlor) or acid to your hot tub for any reason. These chemicals may damage components within your hot tub, burn or irritate your skin, create a rash, and void the manufacturer warranty.

where is Trichlor found? I am guessing with the acid it must be diluted first.

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tri chlor is a tablet, it comes in a 1 inch tablet or a 3 inch, and no...you dont want to use them in your hot tub. Plus they also contain CYA. They are very low on the PH scale. Acid is dangerous to work with, thats why most people use PH down (sodium bisulfate) it is easier to handle and store.

Try cleaning the pleated filter with more than just water, filter cleaner from you psupply store or some people use tsp. Make sure to rinse them out really well or it will cause more issues. maybe the oils from the plastics are trapped in the filter and causing some of this issue. your combined chlorine reading should be dropping as you shock the tub, this is why your chlorine demand is still high, because the CC is still high. You have to shock the tub high enough and keep the reading high enough to get that number down. I think a decontamination procedure may be in order if you cant get the reading right.

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tri chlor is a tablet, it comes in a 1 inch tablet or a 3 inch, and no...you dont want to use them in your hot tub. Plus they also contain CYA. They are very low on the PH scale. Acid is dangerous to work with, thats why most people use PH down (sodium bisulfate) it is easier to handle and store.

Try cleaning the pleated filter with more than just water, filter cleaner from you psupply store or some people use tsp. Make sure to rinse them out really well or it will cause more issues. maybe the oils from the plastics are trapped in the filter and causing some of this issue. your combined chlorine reading should be dropping as you shock the tub, this is why your chlorine demand is still high, because the CC is still high. You have to shock the tub high enough and keep the reading high enough to get that number down. I think a decontamination procedure may be in order if you cant get the reading right.

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I had this problem with a new tub too. It would eat all the chlorine in 24 hours with no usage (even after a decon). I unplugged the ozonator -- problem solved. If you search around this forum, you'll find some details about the interaction of ozone and chlorine. While the ozonator sounded like a great idea when I bought the tub, in practice, I found it too difficult to manage the chlorine. After turning it off, the chlorine demand has been completely predictable.

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I had this problem with a new tub too. It would eat all the chlorine in 24 hours with no usage (even after a decon). I unplugged the ozonator -- problem solved. If you search around this forum, you'll find some details about the interaction of ozone and chlorine. While the ozonator sounded like a great idea when I bought the tub, in practice, I found it too difficult to manage the chlorine. After turning it off, the chlorine demand has been completely predictable.

Yes, I have been noticing the chlorine demand is still high. I need to put at least 6-8oz of bleach every day regardless if I use the tub or not just from keeping it from dropping to zero. I thought once I refil the tub, the chlorine demand won't be so high. Also, the CC is not coming down.

I have been reading on this forum about the ozonator will consume the chlorine if there isn't any bacteria. I am still learning about this one. When I was buying the tub the sale person explained that the ozonator breaks down the bacteria into something that is more easily sanitized by the chlorine. Anyway, that is what I understood.

Still learning every day and thanks for your help. I may come to the same conclusion and unplug that ozonator.

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An ozonator primarily oxidizes bather waste as that is the primary consumer of chlorine in more heavily used spas (i.e. used every day or two). Ozone will kill bacteria directly -- chlorine doesn't need much help in that area. What ozone can do is to inactivate protozoan oocysts much faster than chlorine, but those are less common unless you have someone with diarrhea use the spa.

Ozone can reduce chlorine to chloride and oxidize chlorine to chlorate, thereby increasing chlorine demand that becomes noticeable if a spa is not used. Normally, we see this as a doubling of demand from 25% to 50% over 24-hours. You seem to be seeing more like 100% over 24 hours which may mean your ozonator is exceptionally powerful or that something else is going on or your chlorine level is too low to begin with. If you started with something like 4 ppm FC and it was all gone in 24 hours, then that is quite unusual even with an ozonator.

Note that I am assuming that there is some CYA in the water with the chlorine, so that you are using Dichlor at least initially. If you don't have any CYA in the water, say by using bleach or lithium hypochlorite without first using Dichlor, then the chlorine can dissipate faster even outgassing and maybe getting destroyed by ozone faster as well (I'm not sure if ozone destroys the chlorine bound to CYA -- I suspect that is far slower).

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This may be a dumb question, but if the ozonator kills bacteria and viruses then why do you need chlorine at all?

Because it only kills what gets circulated through the circulation system so does not provide sanitation in the bulk water. It won't affect person-to-person transmission of disease nor will it affect any pathogens attached to spa surfaces. Ozone does not leave a significant residual in the water -- if it was at high enough output to do so, then it could outgas ozone and be a health hazard so they intentionally limit output to prevent this, including turning it off while you are in the spa.

Did you ever decontaminate your spa and use something like Spa System Flush (I had mentioned that in an earlier post)? Maybe you've got significant biofilms somewhere on some surfaces (such as piping or filter) that developed when the spa was new and wet tested or at some later time if the sanitizer level got to zero for a few hours or longer.

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