Ph Level Alkalinity And Cya

[styro]

We have had our Hot Tub since Dec 10th, just got the Taylor 2600 Test kit on the 23rd, prior to that we were testing with a basic Taylor kit (5 drops for each) the Chlorine and pH and it would be all over the place, since we were just adding Dichlor product up to 2 capfuls a day. Not sure of exact measurement. Any how now after using Taylor Test kit this is where we are at and I am concerned that our CYA is way to high (off the scale above 100) and could cause damage to Spa heater and other components, also from what I've read on here the TA and CH are also to high. Note: The company that set us up with Spa did not go over spa chemical regimen correctly. Although, with our below readings the Pool Calculator (referred to on this forum many times) says our CSI is 0.02, which my husband says is good and we don't need to worry about the CYA, or high TA. Please inform as to what we should do, like drain half (or all) the water out and refill? now that we have read this forum (after the fact of this first fill) we know how to do it right from the get go. But at the point we are at now we are unsure if there is a way to fix this, or is everything ok as my husband thinks it is. He plans on adding the Clorox Bleach as needed (and as calculated by the Pool Calculator) since we will measure the FC and CC, and pH everyday.

395 Gallons, 98 degrees, but 100 degrees two hours out of the day. Bathing daily two adults, and 3 times a week to children. No suntan lotion, we live in Tucson and Spa is under covered patio and not getting sunlight.

All in ppm

FC 4.5

pH 7.6

TA 190

CH 80

no test on borate or salt done

CYA (off scale) logged as 100

Stop adding dichlor after reaching 30ppm of CYA!

Now you can switch to Bleach.

Right now You have to much of CYA from using dichlor.

The only option you have right now is to drain your tab and do new refill.

From our advisers we learn: to much of CYA will prevent from your chlorine to work propertley.

Also TA 190 dose not look right.My TA is around 60 and my PH like to rise to around 7.7-.7-8.

Impossible 190 TA will keep you stable at 7.6 PH.Please retest your TA.

Dichlor will lower your TA and PH as well.

Good luck!!!

[chem geek]

Remember that using Dichlor is net acidic because the consumption/usage of chlorine is acidic. So having a higher TA but using Dichlor-only can have the pH be more stable. It's only when switching to a hypochorite source of chlorine, such as bleach, that you need a lower TA since there is no net acidity that needs to be balanced by carbon dioxide outgassing causing the pH to rise.

Nevertheless, getting the CYA to over 100 in just 13 days would take around 8.5 ppm FC of Dichlor added per day. That's around 0.8 ounces per day or 1.6 tablespoons (4.8 teaspoons) or enough for around 1-1/3 person-hours of soaking per day which sounds roughly correct given 2 adults plus having kids half the time. In such a heavily used tub, the CYA level will build up quickly and you would probably switch to using bleach after just 4 days.

[MattMoe]

Ok, we drained the tub, and rinsed the filter. I also cleaned away any water line (very minimal) visible with celo sponge that had soft scub side to it. After tub was full and heated for a little while my husband added 1 oz of Dichlor, and tub was only at 75 degrees. Again we have 395 gallon tub, plus an ozonator.and a spa frog sitting in first filter bin. So now our reading shows the following, but since we are just starting he did not measure CYA, since he said it is still low:

Well by calc notTaylor K-2006 test kit measurement- FC 10, CYA 11

ByTaylor K-2006 Test kit:

TA 110

CH 70

Ph 7.4

CSI -0.57

I have read on here that the ideal TA is 50-60 ppm and CH is 150 ppm, and pH 7.4-7.8, CYA 20-30 ppm, FC 3-6 ppm everyday, and bump up to 12 ppm once a week. So our question is do you agree with those suggestions and would the TA change on it's own over the next several days as water temp increases and the process of adding portions of the total calculated 91 grams of Dichlor, in order to get our CYA to 30ppm and FC to 3-6ppm. Or another way to ask this is should we adjust the TA now or after we get CYA and FC to recommended levels; by doing Muriatic acid and aeration method (mentioned on this forum). Plus can we leave the CH where it's at or should we increase it with a Calcium Hardness increaser by SpaGuard, and if so at what point (like after we get CYA and FC to correct levels). Also if we use the tub while trying to get the CYA to 30ppm do we need to add even more Dichlor than the 91 grams, if so how much for our 395 gallon tub/ per person for 1/2 hour soaks.

[MattMoe]

Ok, we drained the tub, and rinsed the filter. I also cleaned away any water line (very minimal) visible with celo sponge that had soft scub side to it. After tub was full and heated for a little while my husband added 1 oz of Dichlor, and tub was only at 75 degrees. Again we have 395 gallon tub, plus an ozonator.and a spa frog sitting in first filter bin. So now our reading shows the following, but since we are just starting he did not measure CYA, since he said it is still low:

Well by calc notTaylor K-2006 test kit measurement- FC 10, CYA 11

ByTaylor K-2006 Test kit:

TA 110

CH 70

Ph 7.4

CSI -0.57

I have read on here that the ideal TA is 50-60 ppm and CH is 150 ppm, and pH 7.4-7.8, CYA 20-30 ppm, FC 3-6 ppm everyday, and bump up to 12 ppm once a week. So our question is do you agree with those suggestions and would the TA change on it's own over the next several days as water temp increases and the process of adding portions of the total calculated 91 grams of Dichlor, in order to get our CYA to 30ppm and FC to 3-6ppm. Or another way to ask this is should we adjust the TA now or after we get CYA and FC to recommended levels; by doing Muriatic acid and aeration method (mentioned on this forum). Plus can we leave the CH where it's at or should we increase it with a Calcium Hardness increaser by SpaGuard, and if so at what point (like after we get CYA and FC to correct levels). Also if we use the tub while trying to get the CYA to 30ppm do we need to add even more Dichlor than the 91 grams, if so how much for our 395 gallon tub/ per person for 1/2 hour soaks.

Forgot to mention that we do plan on switching to Clorox bleach after getting CYA to 30ppm.

[MattMoe]

Ok, we drained the tub, and rinsed the filter. I also cleaned away any water line (very minimal) visible with celo sponge that had soft scub side to it. After tub was full and heated for a little while my husband added 1 oz of Dichlor, and tub was only at 75 degrees. Again we have 395 gallon tub, plus an ozonator.and a spa frog sitting in first filter bin. So now our reading shows the following, but since we are just starting he did not measure CYA, since he said it is still low:

Well by calc notTaylor K-2006 test kit measurement- FC 10, CYA 11

ByTaylor K-2006 Test kit:

TA 110

CH 70

Ph 7.4

CSI -0.57

I have read on here that the ideal TA is 50-60 ppm and CH is 150 ppm, and pH 7.4-7.8, CYA 20-30 ppm, FC 3-6 ppm everyday, and bump up to 12 ppm once a week. So our question is do you agree with those suggestions and would the TA change on it's own over the next several days as water temp increases and the process of adding portions of the total calculated 91 grams of Dichlor, in order to get our CYA to 30ppm and FC to 3-6ppm. Or another way to ask this is should we adjust the TA now or after we get CYA and FC to recommended levels; by doing Muriatic acid and aeration method (mentioned on this forum). Plus can we leave the CH where it's at or should we increase it with a Calcium Hardness increaser by SpaGuard, and if so at what point (like after we get CYA and FC to correct levels). Also if we use the tub while trying to get the CYA to 30ppm do we need to add even more Dichlor than the 91 grams, if so how much for our 395 gallon tub/ per person for 1/2 hour soaks.

Forgot to mention that we do plan on switching to Clorox bleach after getting CYA to 30ppm.

Also just thought of something, if we need to lower TA could we add MPS and then aerate to raise pH back up.

[quantumchromodynamics]

The total amount of dichlor you should use is 90 grams and then you switch to bleach.

1 ounce (weight) (or 0.9 ounce volume) of dichlor will raise your free chlorine by 10.5 ppm and your cyanuric by 9.56 ppm.

The amount you use each day will depend on how much you need to add to keep the chlorine in the 1 to 4 ppm range. Each tub has a baseline amount of chlorine it uses every day. See the post on Chlorine Demand for more details.

In addition to the baseline amount of chlorine a tub needs every day, it needs about 13 grams of dichlor or 1 ounce of MPS per person-hour. Ideally, you will raise the chlorine level to a level sufficient today to make sure that you never go below 1.0 ppm by the next day.

Once you switch to bleach, maintain a chlorine level of 2 to 5 ppm. Add about 4 fluid ounces of bleach or 1 ounce of MPS per person-hour of tub use. Adjust as necessary to maintain consistent levels.

Be careful to get the right bleach. Regular, unscented 6.00 % sodium hypochlorite. Don't use any sort of "special" bleach, such as scented or splashless.

Your Total Alkalinity is OK for now. You determine the correct TA by watching your pH level. If the pH is constantly too low, then your TA is too low. If the pH is constantly too high, then your TA is too high. If the pH is constantly good, then your TA is good. You will probably need to lower it once you switch to bleach. To lower your alkalinity, follow the lowering alkalinity post.

I would leave the calcium at 70 ppm right now until you switch over to bleach and you see where your pH and TA will end up. Wait until you get all of your chemicals balanced to see if you want to go any higher. I think that 100 ppm is a good level.

You should determine your CSI based on the highest temperature your water will get to. If you plan to heat it to 104 F, then that's the temperature you should use in thepoolcalculator. Try to stay in the -0.3 to 0.0 range.

Always allow plenty of time between chemical additions. If you add different chemicals too closely together, then you could get a bad reaction. Try to allow about 1 hour between additions of different chemicals.

[MattMoe]

The total amount of dichlor you should use is 90 grams and then you switch to bleach.

1 ounce (weight) (or 0.9 ounce volume) of dichlor will raise your free chlorine by 10.5 ppm and your cyanuric by 9.56 ppm.

The amount you use each day will depend on how much you need to add to keep the chlorine in the 1 to 4 ppm range. Each tub has a baseline amount of chlorine it uses every day. See the post on Chlorine Demand for more details.

In addition to the baseline amount of chlorine a tub needs every day, it needs about 13 grams of dichlor or 1 ounce of MPS per person-hour. Ideally, you will raise the chlorine level to a level sufficient today to make sure that you never go below 1.0 ppm by the next day.

Once you switch to bleach, maintain a chlorine level of 2 to 5 ppm. Add about 4 fluid ounces of bleach or 1 ounce of MPS per person-hour of tub use. Adjust as necessary to maintain consistent levels.

Be careful to get the right bleach. Regular, unscented 6.00 % sodium hypochlorite. Don't use any sort of "special" bleach, such as scented or splashless.

Your Total Alkalinity is OK for now. You determine the correct TA by watching your pH level. If the pH is constantly too low, then your TA is too low. If the pH is constantly too high, then your TA is too high. If the pH is constantly good, then your TA is good. You will probably need to lower it once you switch to bleach. To lower your alkalinity, follow the lowering alkalinity post.

I would leave the calcium at 70 ppm right now until you switch over to bleach and you see where your pH and TA will end up. Wait until you get all of your chemicals balanced to see if you want to go any higher. I think that 100 ppm is a good level.

You should determine your CSI based on the highest temperature your water will get to. If you plan to heat it to 104 F, then that's the temperature you should use in thepoolcalculator. Try to stay in the -0.3 to 0.0 range.

Always allow plenty of time between chemical additions. If you add different chemicals too closely together, then you could get a bad reaction. Try to allow about 1 hour between additions of different chemicals.

Thank you very much for taking the time to help/respond. we plan to follow your advice. Happy Holidays.

[styro]

Yes, check the cyanuric acid level every few weeks, and if the level is low, use dichlor until the cyanuric acid level is back up to 30 ppm.

I think that anywhere in the -0.3 to 0.0 range is good. Use the pool calculator to calculate your CSI and adjust as needed. I think that using a target of -0.15 will give you a margin of error so that your pH can fluctuate a little bit without putting you outside the range.

Happy New Year,

So far so good with my water chemistry.The only ph trying to stay or exit 7.8 range and my TA is low 49.

I was wandering if I ever reach the 7.5 range or if I do my then my buffer will need to be around 20 or less.which I fill is not right(to low).

What make the difference for some people to get the target PH 7.4-7.8 with TA in range 60+??.

My numbers are:

F.ch - 2.34

T.ch - 2.57

PH - 7.8

TA - 49

CYA - 26

I did add BORAX and borate level was 50 ppm.

My question is after testing again my CYA level and I will find out the CYA level is low I will add

Dichlor, what about BORAX?Do I need to add borax to reach borate 50 ppm level again or that will stay till next refill?

Thanks

Adam

[chem geek]

Adam,

You might have so much aeration in your tub that a TA of 50 ppm and a pH of around 7.7 to 7.8 is where it is much more stable. Do you have an ozonator and does it run frequently? Ozonators can generate additional bubbles that aerate the water for much longer periods of time. Do you keep your hot tub covered and is it well sealed? If it is uncovered with aeration, that will outgas carbon dioxide faster. At a pH of 7.8 with the rest of your numbers, the amount of carbon dioxide in the water is about double its equilibrium concentration with the air while at a pH of 7.5 it's around 4.5 times higher in the water than the equilibrium concentration. I wouldn't worry at all with a pH of 7.7 as your CSI is reasonable there and if you find this is the most stable pH then you can use a somewhat lower CH on the next refill if needed.

How are you getting such precise measurement numbers? This doesn't sound like anything from a Taylor K-2006 test kit. You also didn't list the CH number though in the past you noted 157-170 which probably has not changed.

Also, what kind of bleach are you using? Clorox Regular unscented 6% bleach has the least amount of "excess lye" in it. Off-brand Ultra bleaches (which are also 6%) have far more excess lye so would cause the pH to rise at a rate of around 0.18 or more per week (without borates; with 50 ppm Borates it's around 0.05 or more per week) if you added around 4 ppm FC per day. With the Clorox bleach, there is virtually no extra pH rise from the bleach (extra lye) itself after accounting for chlorine usage. There is some pH rise from chlorine outgassing itself, but that should be a fairly low rate.

The borates level should stay the same and you won't need to adjust it until the next refill.

Richard

[styro]

Adam,

You might have so much aeration in your tub that a TA of 50 ppm and a pH of around 7.7 to 7.8 is where it is much more stable. Do you have an ozonator and does it run frequently? Ozonators can generate additional bubbles that aerate the water for much longer periods of time. Do you keep your hot tub covered and is it well sealed? If it is uncovered with aeration, that will outgas carbon dioxide faster. At a pH of 7.8 with the rest of your numbers, the amount of carbon dioxide in the water is about double its equilibrium concentration with the air while at a pH of 7.5 it's around 4.5 times higher in the water than the equilibrium concentration. I wouldn't worry at all with a pH of 7.7 as your CSI is reasonable there and if you find this is the most stable pH then you can use a somewhat lower CH on the next refill if needed.

How are you getting such precise measurement numbers? This doesn't sound like anything from a Taylor K-2006 test kit. You also didn't list the CH number though in the past you noted 157-170 which probably has not changed.

Also, what kind of bleach are you using? Clorox Regular unscented 6% bleach has the least amount of "excess lye" in it. Off-brand Ultra bleaches (which are also 6%) have far more excess lye so would cause the pH to rise at a rate of around 0.18 or more per week (without borates; with 50 ppm Borates it's around 0.05 or more per week) if you added around 4 ppm FC per day. With the Clorox bleach, there is virtually no extra pH rise from the bleach (extra lye) itself after accounting for chlorine usage. There is some pH rise from chlorine outgassing itself, but that should be a fairly low rate.

The borates level should stay the same and you won't need to adjust it until the next refill.

Richard

Richard,

Thanks a lot for all your help.

I do my tests with ColorQ PRO 7-PLUS digital meter.

My ozonator runs 2 times a day 1hr each.

The bleach I'm using is Clorox Ultra 6% bleach.

My Ch when I last tested was 220.

Thanks again

Adam

[chem geek]

One other thing to mention is that the pH should be measured at the same FC level. When you add the bleach and the FC rises, the pH will be higher as well and then as the FC drops the pH may drop unless there is carbon dioxide outgassing to offset it. With 50 ppm Borates, this swing in pH is roughly cut in half.

So other than not trying to fight to get to 7.5 or perhaps seeing what happens if the TA even gets to 40 ppm, I'm not sure what to tell you. You could always add acid regularly or even MPS weekly (since that is acidic), but then would need to add some baking soda as well on occasion. This would be similar to what happens in the Dichlor-only method since Dichlor is essentially net acidic and one needs to add baking soda on occasion to maintain the TA. The idea, however, with the Dichlor-then-bleach method is to get the TA to a level where you don't need to add acid or baking soda very often and you aren't there yet, for whatever reason.

Since you have a meter that measures pH (and other things) so easily, you might see if you can figure out when the pH is rising most quickly. Is it from your using the tub with aeration jets on? Is it during the period the ozonator is on? How much pH change is there with no jets running, no ozonator running, and the spa covered? How much does the pH rise from addition of bleach (after 10 minutes of mixing)?

[styro]

Hi there,

Finlay my numbers are looks ok.

I do test my water every day with the strips and at lest 2 times a week with my ColorQ digital tester.

I did some adjustment adding more PH minus a week ago.

Last week numbers with ColorQ before soak:

F.ch = 2.82

T.ch = 2.08

PH = 7.6

TA = 42

CYA - 28

temp = 99

I did not use my tub for a week.

Last night after 30 min soak:

F.ch = 1.84

T.ch = 2.06

PH = 7.6

TA = 44

CH = 202

CYA = 27

temp = 29

The PH looks stable at 42-44

I wish to be at 50'-60' i will fill more comfortably.

My CYA do not drop much for 3 weeks stays almost same.Is that normal?

How often I should retest my CYA and do ajustment?

Thanks

[chem geek]

If the TA is near 40, that's OK. You can always increase either CH or the pH target or both to get the saturation index closer to zero. To get more pH buffering, however, you can use 50 ppm Borates. That's what most people do if they find they have to have a very low TA for pH stability.

As for CYA, it will not drop very quickly over time, though it does slowly break down in a spa at roughly 5 ppm per month so once a month you can use Dichlor for a day to bring it back up.

[styro]

If the TA is near 40, that's OK. You can always increase either CH or the pH target or both to get the saturation index closer to zero. To get more pH buffering, however, you can use 50 ppm Borates. That's what most people do if they find they have to have a very low TA for pH stability.

As for CYA, it will not drop very quickly over time, though it does slowly break down in a spa at roughly 5 ppm per month so once a month you can use Dichlor for a day to bring it back up.

In my case Borates did not make any difference with rising my TA level just I've notice softer water.With the next refill I should focus to keep my CH lower then 200 to get the ph faster in range with higher TA?

Can you please give some example of prefect saturation index with numbers.My understanding is to keep F.CH and T.CH as closer numbers possible.

Example: F:ch 1.54 then T.ch 154 and just above will be fine.The higher difference between this 2 numbers then higher saturation index out of.

In case F.ch and T.ch is very out of then the water need to be shock with bleach if we using bleach method up to 10 ppm?

Correct me please if I'm wrong.

Thanks

Adam

[chem geek]

CH is Calcium Hardness and has nothing to do with the chlorine level. Free Chlorine (FC) and Total Chlorine (TC) are two chlorine measurements. When using a FAS-DPD chlorine test (such as in the Taylor K-2006 test kit), then you measure Combined Chlorine (CC) where TC = FC + CC. So when CC gets above 0.5 ppm, or equivalent when TC is more than 0.5 ppm higher than FC, then you probably need to shock with a higher level of chlorine. Usually, it just means you have gotten behind with the chlorine or that you are using Dichlor-only and the CYA got too high as that slows down chlorine speed of getting rid of bather waste.

As for the saturation index that you can calculate using The Pool Calculator, you can target something around -0.2 though you don't have to be too picky about it except to make sure it's not more than 0. Targetting something lower helps prevent scale in case your pH gets higher than you expect.