HIGH - PH, Cyanuric acid, Total Chlorine & Bromine

[Jeff Mack]

(EDIT: This did seem to start when we went on vacation for about 4 days so I bought a floating chlorine dispenser.  So instead of using "SpaGuard Chlorine" powder I stuck a bunch of 1 inch chlorine tablets into the dispensor, which for the first time chlorine levels were reading super high.  Not sure if this has anything to do with it)

(EDIT 2: Also for the last 8 months, since we bought the hottub new, I ALWAYS had a hard time keeping enough chlorine.  It's only me that uses the tub almost everynight, and Im usually showered, and I always added Chlorine powder after getting out, but it would read usually zero the next morning.)

First time poster.  We are kinda new owners of our Napali 250 gallon hot tub for about 8 months now.  Numbers have been working fine, only had to add chlorine  for the most part after every use or so.  

So the problem is for the last couple of weeks the TA and pH were super high.  I've read a couple posts on here and realized I need to bring the pH down with Muriatic Acid which I bought last night at hardware store.  PoolCalculator.com told me to add .6oz of acid, (which i did VERY carefully, started with a clear solo cup which i filled half way with spa water first then while on the zero'd out scale added .6oz, then poured that, very carefully, into a 5 gallon bucket which was half full of spa water, then and only then did i add to center of spa, being careful not to splash. 

I have done this about 6 times now in the past 24 hours, with the last two I used about 2 oz of acid, since it wasn't really changing things.  

Each time I ad Muriatic acid, I wait about 5 minutes then run the spa for about 15 minutes.  Then I recheck with JNW test strips, (off amazon), within about an hour

Here are my numbers now; 

Total Chlorine 20 (high)

Free Chlorine 4

Bromine 40 (high)

TA 90

Cyanuric Acid 240+ (color is off the chart)

PH 8.6++. (color is off the chart)

I just ran these numbers above on poolcalculator.com on my laptop for the first time, (all previous times I use my phone), and it says to drain and replace 79% of the water under the Cyanuric acid section.

 

Thanks,

Jeff

 

[Jeff Mack]

Well, I read a little bit more last night and decided to drain most of the water, (about 80%).  Just refilling now off the washing machines hot water line with garden hose attached to Great Barrier inline filter.

Still not sure how these numbers got so out of wack all of a sudden.  But it did seem to directly coincide when I started to use the floating chlorine dispenser with 1" chlorine tablets approx 1 month ago.  So I'll go back to the  "Spaguard Chlorinating Concentrate" and not use the floater or the 1" tablets.

[Jeff Mack]

Hahahahaha!  No wonder no one responded, my thread is still waiting for approval!  lol!  O well, it's been fun talking to myself! lol

[waterbear]

First, about approval of posts: All new members have to wait for post approval. Once you are an established member that requirement goes away. Moderators such as myself who approve posts are volunteers and do this in our spare time so sometimes there is a delay but most posts are approved withing 24 hours and it's only been 19 since you posted.

[waterbear]

Several things that I will be commenting on.

1) The SpaGuard chlorinating concentrate you have been using is responsible for the high CYA much more so than the HTH chlorine tabs (which should never be used in a hot tub) are. The granules are dichlor, which adds 9 ppm CYA for every 10 ppm chlorine added and will cause CYA to rise rapidly. The tabs are trichlor that adds 6 ppm CYA for every 10 ppm FC added so they won't cause the CYA to rise as fast as dichlor will. HOWEVER, trichlor dissolved faster in hot water as found in a hot tub, which probably explains your very high chlorine levels. Also, trichlor is extremely acidic and can quickly cause a severe pH drop in the small body of water found in a tub and can also quickly cause the TA to drop. THe low pH can cause damage to pump seals, heaters, filters, and plastic parts in the tub. DO NOT USE TRICHLOR IN A HOT TUB!

2) 

19 hours ago, Jeff Mack said:

I always added Chlorine powder after getting out, but it would read usually zero the next morning.

This is often normal when manually dosing chlorine.

19 hours ago, Jeff Mack said:

So instead of using "SpaGuard Chlorine" powder I stuck a bunch of 1 inch chlorine tablets into the dispensor, which for the first time chlorine levels were reading super high.  Not sure if this has anything to do with it

It did

3)

19 hours ago, Jeff Mack said:

So the problem is for the last couple of weeks the TA and pH were super high

and your TC was very high also, correct?

19 hours ago, Jeff Mack said:

Total Chlorine 20 (high)

Free Chlorine 4

Bromine 40 (high)

TA 90

Cyanuric Acid 240+ (color is off the chart)

PH 8.6++. (color is off the chart)

 

First, strips are useless for water balancing. they do not have either the precision to balance water. For example TA should be balance withing a +/- 10 ppm range and the best strips are capable of are +/- 40 ppm. Also, while strips are precise (they will give the same results when doing repeated tests on the same sample) they are not accurate (that the test result obtained is a accurate measurement of the actual value of the water parameter being tested. I would strongly recommend investing in a Taylor Technologies  K-2006 test kit which uses the FAS-DPD test method for chlorine and also tests pH with acid and base demand to calculate how much acid or alkali is needed for a specific pH change in YOUR water at the time of the test, which no calculator can do. It also tests cyanuric acid, TA, and calcium hardness. Strips only test total hardness (calcium and magnesium hardness) which is useless for water balancing.  Do not get the K-2005 which uses DPD testing and suffers from bleachout, as the FC test in your strip bleached out. Your FC is MUCH higher than 4 ppm. The Total chlorine and the bromine tests on your strip do not use DPD testing and give a more accurate representation of your chlorine level. I will explain a bit further on.

Here is a link to videos on the Taylor Technologies website that shows the kit in action.

https://www.taylortechnologies.com/en/page/231/k-2006-complete-kit-with-fas-dpd

It is the best investment you can make to care for your spa water. You can buy it online on such retailers as Amazon and many online pool and spa supplies. Unfortunately, most brick and mortar stores that carry Taylor test kits usually carry the slightly less expensive K-2005, which you do not want. (No, I don't nor have I ever worked for Taylor Technologies and I do not receive any kickback from them. I have just found their kits to be the most reliable and easiest to use over my many years of experience.

Now getting to your test results. Several things jump out:

Your FC is 4 and by the color of the color block this is a DPD test. DPD bleaches out at high chlorine levels and I would guess your FC is in the neighborhood of 20 ppm since your TC is reading 20 and your bromine is 40. Bromine readings are double the total  chlorine reading (actually 2.25 higher but most test kits just double the scale)  The Total chlorine test and the Bromine test are using a different reagent that does not bleach out but can only give a Total chlorine or Total Bromine reading. With chlorine spas we are interested in FC (good chlorine) and we test total chlorine to see if there is any combined (bad) chlorine, CC, that does not sanitize but causes eye irritation and gives off a strong "chlorine" smell. If the CC is .5 ppm or higher the spa need to be shocked to destroy the CC. With bromine we test total bromine because, unlike chlorine, combined bromine IS an effective sanitizer. The chemistry of bromine is different than the chemistry of chlorine. Also, you either have chlorine or bromine, not both, so in your case ignore the bromine scale on your test strip. If you were using bromine you would ignore the FC, TC, and CYA scales on the strip (CYA does not stabilize bromine and is not used in bromine tubs).

CC is calculated by subtracting the FC from the TC. The FAS-DPD test in the K-2006 directly measures CC so no math is needed.

4) THIS IS THE MOST IMPORTANT PART OF THIS POST! READ AND UNDERSTAND THIS!

HIGH SANITIZER LEVELS WILL CAUSE pH TO READ HIGH WHEN IT IS NOT!!!!!!!!!!

Read this:

https://www.poolspaforum.com/forum/index.php?/topic/58991-false-high-ph-readings-when-shocking-some-truths/

Now read it again!

The FC test on your strips bleached out and gave a false low reading but the TC and Bromine tests told the truth. Your sanitizer level was much too high to try and test pH. The FAS-DPD test in the K-2006 does not suffer from bleachout like DPD testing does.

By adding all the acid you added you ran the risk of causing permanent damage to your spa. It is a good thing you drained the spa and refilled it.

As far as your CYA and TA reading go, once again the high chlorine level probably had an impact on their accuracy but the CYA test on strips is not known to very precice, it's more of an 'in the ballpark' reading but for a spa you want to keep the CYA in the 20 to 30 ppm range. I suggest you read about the Dichlor/bleach method for chlorine which uses dichlor to get the CYA into target range and then you switch to sodium hypochlorite (liquid pool chlorine/shock or chlorine laundry bleach--same thing except for the strength) to chlorinate after every soak and to shock with when CC is .5 to 1 ppm or greater. It is often hard to achieve a CC of 0 ppm in a spa because of the bather to water ratio. If you have persistent CC greater than 1 ppm there are other measures you can take to lower it.

https://www.poolspaforum.com/forum/index.php?/topic/59160-dichlorbleach-easypeasy/

https://www.poolspaforum.com/forum/index.php?/topic/23090-dichlorbleach-method-in-a-nutshell/

https://www.poolspaforum.com/forum/index.php?/topic/53108-some-truths-on-bleach-dosing/

 

You might as well also read this to understand the relationship between pH and TA and how to adjust it

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

https://www.poolspaforum.com/forum/index.php?showtopic=28846

I hope I answered your questions. My recommendations:

1) Stop using strips and get the Taylor K-2006

2) read all the linked posts above

3) reread them

4) post any questions you might have and we wil try to answer them.

5)don't be afraid of the chemistry, it's not rocket science. While there is a bit of a learning curve it's really easy once you have an understanding of what's going on in your water.

Parameter for your water:

FC 4 to 6 pppm

CC .5 ppm or lower. If it's higher shock the water with liquid chlorine or laundry bleach to 12 to 15 ppm (assuming CYA of 20 to 30 ppm). DO NOT TRY TO TEST pH WHEN FC IS ABOVE 10 ppm!

CH ideally 120 to `150 ppm to help avoid foaming. (soft water is more likely to foam than harder water. If the CH of your fill water is higher but below300 ppm don't worry about it. If it's above 300 ppm you might want to consider regular additions of a phosphonate based metal or calcium sequestrant. in my experience I have found the EDTA based ones to be not as effective.

TA 50 ppm to 70 ppm for optimum pH stability, It can be as low as 40 ppm if needed. 

pH for optimum pH stability NO LOWER than 7.6. Don't lower it until it hits 8.0 

CYA 20 to 30 ppm. Chlorinate with dichlor (your SpaGuard granules) until the CYA is 20 to 30 ppm then switch to liquid chlorine or chlorine laundry bleach.

You might want to consider adding 50 ppm borate to your water (boric acid is the easiest way but you can buy a commercial borate additive such as Proteam Gentle Spa. Besides the algaestaic and water softening properties it will also give you a secondary pH buffer system that will lock your pH around 7,8 for an extended period.

 

[Jeff Mack]

@waterbear Thank you!  And I do appoligize if my reply came off rude.  I should have realized it would take time for my first post to be approved.

I was aware that there was a lot more to learn. Thanks for all the advice, and education really.  While draining and refilling fixed the problem for now, I am going to order the taylor k-2006 now.  I will also cease using the tablets and thanks again for the great explanation on that.

Is this the correct test kit; K-2006c (I assume for chlorine instead of salt);

https://a.co/d/eSzyGYE

[waterbear]

The K-2006C comes with 2 oz. reagent bottles and is designed for a service professional that tests many pools. The K-2006  comes with 3/4 oz. bottles. While it might seem the larger bottles are a better value you need to know that regents do have a shelf life (depending on the reagent) and do need to be replaced every year or two, depending on where you store the kit. If the price is good for the C kit I would get it and that does seem like a good price. The K-2006 is cuurently going for $82 on Amazon.

https://www.amazon.com/Taylor-Complete-Swimming-Chlorine-Alkaline/dp/B004BGF7TI/ref=sr_1_2?crid=5O0I7RLTP8XW&dib=eyJ2IjoiMSJ9.BKW1O5QHptXnZ6mgabCVUS5dC2nKlVpP_JI1lhxCMt9yxqcPM8gKMYJ6CiJi8mWri7Ym3T-qTYugLXPmyawBM2saT7CZHlPvfw0dCqxAmY9ebjnFb1JVwSTNYNLpWWRJInMZFYXdomyi16V12_UA_wg_AMEXcHLfqxPDMYnbMnOFt5wTuv1ulJU1fENgVXNoIjsv37lGmQE1eKvFjFeJcgqzgWijC4znwpzwdZbv2C26i99ULGnwuI8bv_muBOJQHZbhbQnhWS5iyEbvvjvxyw.-vO6hZNtxBLobTUyzXH6iYPAVYf9w487zFjTP7h6n4c&dib_tag=se&keywords=K-2006&qid=1746388388&s=lawn-garden&sprefix=k-2006%2Clawngarden%2C138&sr=1-2

The C denotes the 2 oz. size of the reagent bottles. Taylor has several such designations for sizes up to a gallon.

This kit is designed for chlorine but it can also test bromine by running the FC test and multiplying the results of that test by 2.25. The CYA test is not used with bromine. Taylor also has the K-2106 kit for bromine only that directly gives a bromine reading. It does not include the CYA test  and cannot be used for chlorine since it lacks that test and the test for combined chlorine. Hope this helps.

Salt pools ARE chlorine pools, the generators produce sodium hypochlorte (liquid chloirne, bleach). The tests are identical. The salt kit also includes a test for chloride (salt) in the water. However most SWCGs have a readout that gives the salt level and that is normally sufficient. In the case where there is no salt readout then a salt test (which they also sell as a stand alone test) or the use of a salt titrator strip from Hach or AquaChek is a good addition to your testing arsenal. (The only two test strips that I have found useful are the salt titrator strips, which need to sit in a cup of the sample water which rises through a column of reagent on the strip over 5 minutes or so before it is read, and borate test strips from either LaMotte or Industrial Test Systems since they have color blocks that are easy to read. The borate strips by Taylor, Hach, and Aquachek all have color block that are very close shads of tan and very difficult to read, IMHO.)