Hot Tub Forum
Original => Hot Tub Forum => Topic started by: CapMorgan on December 29, 2006, 06:17:39 pm
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Hello all,
I been having a problem with my PH and TA it is always high my water is 2 months old and when ever i balance my water the next day the numbers are high again.
When i balance the water
PH 7.2
TA 100
Because i have a problem with my water just to check to see what is going on the next day my numbers are high again
PH 8.0 or higher
TA 120
I am not trying to micro manage my water but i really feel my numbers should not get that high in 1 day and the odd thing is when my tub was brand new and on my first water fill my PH and TA would always go lower in a week's time since i drained my tub and added new water the water is doing the opposite.
I have been having a problem with my skin with rashes and itching a lot and i really feel that it is because i always have a High PH level can anyone help in why my PH would rise so fast in 24 hours.
CapMorgan :-[
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You can get false readings if you test the water in the first few hours after adjusting pH/TA as it takes awhile for the acid to inteact fully with the carbonates. The result you get the next day is the true reading, so I'm guessing you haven't added enough acid yet. It can take a lot of acid to get pH down -- my high pH/high TA fills take over 24 oz of dry acid to balance the water. You just have to keep adding acid until you overcome the alkalinity and get the pH to stay in range. Then if the pH becomes volatile, you can work on increasing alkalinity, otherwise I wouldn't worry about it. If you have any hardness in the water, you may want to consider a stain/scale product to protect the heater and tub surface until you get the tub balanced.
The high pH may be affecting your sanitizer's effectiveness. Dichlor is especially sensitive to high pH. This and/or the caustic effect of high PH is probably the cause of your skin irritation.
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Funny this topic should come up, as I was going to start a new post.
I, also , can not drop my pH below 7.9 no matter what I do. If I add acid, all that drops is the alkalinity, the pH doesn't move a bit.
My reading yesterday alk. 150, pH 7.9. I added 2 tablespoons of pH decrease and got the following readings today. alkalinity 82. pH 7.9
My dealer says quit worrying about it, that the pH is impossible to drop in this town. Now I know nothing is impossible. LOL.
So what do i do? add 1/2 pound of pH decreaser? then worry about the alkalinity?
Everywhere I have read, says do the alkalinity, then do pH. That doesnt work for me.
Neo
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that is funny i always have to add in order to get a reading
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You need to get the alkalinity to a point where the PH will drop. The alkalinity is doing it's job ... locking the pH into place.
I always tell people worry about their PH and only worry about alkalinity only if you see the PH bouncing all over the place.
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In my tub, when the TA gets to 100 or above, my pH starts rising. I keep my TA at about 80 and my pH rarely moves. It may just be my water, but that has been my experience. There have been other posts that are similar to yours...high TA...high pH. Try bringing your TA to the low end of normal and see what it does.
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Ok. My ALK is about 80. My pH is 7.9. I just added 1 1/ oz. of acid again, and I will wait see what happens.
Neo
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Well I finally got the pH to drop. I added about 4 more oz. of pH decreaser. Once the alkalinity got to about 30, the pH starting to plunge quickly. I think it got to about 6.8 for a few minutes, then I brought it back with alk Increaser . I think it is about 7.4 now, and will test again in morning. That will be the real test ; to see if it bounces back. At least I know what ORANGE looks like on a test strip now! ;D
It is amazing to me how low you have to get the alk. before the pH will drop;, at least with my water. All the books say to balance the alk first to 100-125, but that doenst work for me. The water was too stable.
Thanks for the advice.
Neo
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CapMorgan
I saw your post on another forum regarding this matter. The person who replied recommended against what every tub manufacturer instructs to do...that is to use dichlor form of chlorine. As a matter of fact, his instruction to use bleach is in opposition to just about every manufacturer and my void warranties. Now I am a believer in using bleach or liquid chlorine...I use it in my pool...but in the small volume of a spa it does not make sense. The pH is just too high and the problem with handling bleach is a problem...one slip and you could have irrepairable damage. The fear of high CYA has been well documented here and on other forums...I myself check levels periodically, but the fact that you change water on a regular basis really negates any of the problems presented. Although he discredits Vermonter's method, Vermonter's credentials are substantial and his opinions are backed with solid experience and testing. I have watched Vermonters posts intently for years now and have the highest regard for him.
I post this here because I was concerned about the advise and just wanted to present my two cents without having to battle. You can take it for what its worth.
tony
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CapMorgan
I saw your post on another forum regarding this matter. The person who replied recommended against what every tub manufacturer instructs to do...that is to use dichlor form of chlorine. As a matter of fact, his instruction to use bleach is in opposition to just about every manufacturer and my void warranties. Now I am a believer in using bleach or liquid chlorine...I use it in my pool...but in the small volume of a spa it does not make sense. The pH is just too high and the problem with handling bleach is a problem...one slip and you could have irrepairable damage. The fear of high CYA has been well documented here and on other forums...I myself check levels periodically, but the fact that you change water on a regular basis really negates any of the problems presented. Although he discredits Vermonter's method, Vermonter's credentials are substantial and his opinions are backed with solid experience and testing. I have watched Vermonters posts intently for years now and have the highest regard for him.
I post this here because I was concerned about the advise and just wanted to present my two cents without having to battle. You can take it for what its worth.
tony
I didn't read the other forum's post but I agree with tony 110% - the use of dichlor or lithium chlorine in a tub is the way to go. The amounts we use, 1 teaspoon to 3 tablespoons, are so little and effective that using any other forms of chlorine shouldn't be considered.
I too use bleach in my above ground pool and have added gallons at a time to fight off algea. Also as tony said, you are fighting high PH and bleach has a PH of 13 ... If you want to throw something in to oxidize then throw unbuffered MPS which has a PH of 4.
Keep folowing the advice here and your PH and alkalinity will come down.
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Tony & Vinny
I appericate your advice I am new here only had my tub since march of 2006 and since i did my refill i been having nothing but problems with my Ph and TA and i have been suffering from what is the so called hot tub itch. On the other forum the reason why he says to use bleach is because dichlor adds to CYA and once CYA gets to high then chlorine does not work then you will get bacteria then the hot tub itch.
He says that once CYA gets over 20 ppm then chlorine is useless so this morning i checked my CYA level and it is 100 ppm. My water is only 2 months old and my cya is through the roof im really confused now and i have not been in my tub in over a 2 weeks now as every time i use it i itch like crazy i just need to find a solution to my problem so i can start to enjoy my tub again.
CapMorgan <---- at a lost :-[
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First of all that other poster is FULL OF DO-DO!! 20 PPM is really low ... 100PPM is at the high range. Depending on the usage we all will have 100 PPM cya in a couple of months - how much have you used the tub and how many people?
Itching & hot water can go together. Add chlorine and you can have even dryer skin. These irritate some people and don't irritate others. Have you neglected the tub chemical wise and need to hit it with high levels of chlorine (50+ PPM)?
The other thing you can do is partially drain and refill the tub to lower the cya.
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I agree with Tony and Vinny (as I usually do). It sounds as though you are getting some bad advice on the other forum. I think your problems stem from not getting the pH down. As I said before, chlorine is not very effective at high pH. If you have been trying to get by with the small dichlor doses that are often discussed on this and other forums, while running pH over 7.5, it is very possible that you have not had enough sanitizer in killing form in your tub.
You need to keep hitting the tub with acid to get the pH down, and you should consider a super-sanitization to make sure your problems are not related to bacteria growth. Until you get the pH down, you should use larger chlorine doses than normal
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I am the only person who use's the tub and i take a bath before i take a soak 99% of the time. I use the tub daily for about 45 min to 1 hour. (until 2 weeks ago :(
I dont think i have neglected the tub i have a 360 gallon tub and i add 3/4 tsp of dichlor after each use and i shock weekly with 5 1/4 tsp and balance the PH and TA. My water is clear like it was new and it has no odors.
Do you really think i need to hit it with a 50 ppm of chlorine?
After each soak i put on lotion to keep my skin from drying out.
I have been adding 8 ounches of PH down, my TA will goto 100 and my Ph will goto 7.2 then the next day i check it and my TA will be back to 120 and my PH will be 8.0 or higher i have been doing this for 4 days and every day the same thing happens.
What is an acceptable level of CYA?
CapMorgan
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As I said , i am having same problem. My last post said i was down, and now, 4 hours later, my pH is back up to 7.9 and alk is back to 100.
Maybe we will have to do this several more times. I am stumped as well. My water is only 2 weeks old.
Neo
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I am the only person who use's the tub and i take a bath before i take a soak 99% of the time. I use the tub daily for about 45 min to 1 hour. (until 2 weeks ago :(
I dont think i have neglected the tub i have a 360 gallon tub and i add 3/4 tsp of dichlor after each use and i shock weekly with 5 1/4 tsp and balance the PH and TA. My water is clear like it was new and it has no odors.
Do you really think i need to hit it with a 50 ppm of chlorine?
After each soak i put on lotion to keep my skin from drying out.
I have been adding 8 ounches of PH down, my TA will goto 100 and my Ph will goto 7.2 then the next day i check it and my TA will be back to 120 and my PH will be 8.0 or higher i have been doing this for 4 days and every day the same thing happens.
What is an acceptable level of CYA?
CapMorgan
I hate to tell you - your using too little chlorine!
I can get by with 1 teaspoon with a 400 gallon tub and it gives me 1.5 PPM ... but that's at a PH of 7.2. I ran my tub for months at that but then my tub 's PH went high (7.8) and the water went bad. I now use 2 teaspoons for a 3 PPM chlorine level and I know at a PH of 7.8 I have enough chlorine.
I personally would keep at adding PH down as eventually yo will win that battle, then shock the tub with 10 PPM chlorine.
Something that has been mentioned here in other posts is that water gets harder to manage as the TDS gets high - this might be the case with you. In a spa there is no acceptable range of CYA ... you start at 0 and go to ? depending on how much chlorine you use, how often you use it and how long you keep the water.
As I said, dump half the water and see how it goes but if you do dump I would still put in 10 PPM chlorine. If there is a biofilm growing then the 50 PPM will be needed, hopefully that hasn't happened. How to determine there is a biofilm ... I have no clue but I would think that if the PH is correct, you shock the tub and still get the itches - shock with 50 PPM and see a Dr.
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I am the only person who use's the tub and i take a bath before i take a soak 99% of the time. I use the tub daily for about 45 min to 1 hour. I dont think i have neglected the tub i have a 360 gallon tub and i add 3/4 tsp of dichlor after each use and i shock weekly with 5 1/4 tsp and balance the PH and TA. My water is clear like it was new and it has no odors.
If you are bathing, then using the tub for 45-60 minutes, your problems could just be the oils stripping out of your skin from too much time in the water. Lotion can only do so much to counteract the drying effects of hot water. Regardless, I think you need to finish balancing your water, and take a look at your sanitizing program.
First of all, 3/4 tsp is a 1.5 ppm dose in your tub, which IMO is on the light side. Multiply that by the fact that less than 25% of the chlorine in the tub is in the form of hypochlorous acid (the killing form) at a pH over 8, and you have an effective 0.4 ppm killing chlorine. That may be enough given the situation you describe, but I wouldn't count on it. IMO, that is one of the weaknesses of the way people interpret the "Vermonter" system. If the pH isn't low enough to have the majority of the chlorine in acid form, the recommended doses need to be adjusted up.
Before super-sanitizing, you can check the tub by measuring chlorine levels at 2 hrs after you shock with dichlor, followed by an 8-12 hour check, and a 24 hour reading. If most of the chlorine is present after 2 hrs, half of it at 8-12 and something still there the next day, you don't need to super-sanitize, but I still would increase the daily dose. IMO 1.5 tsp would be a safer dose once you have the pH down to 7.5, and I'd be using a tablespoon/day until then.
Now one more time on the pH. As I said before, any readings you take after applying the acid are meaningless, so don't bother. Wait at least 4 hours, better yet the next day, before testing. (Neo, that means you, too ;). The carbonate you added after you saw the orange on your test strip countered anything you gained with the acid) There are only a few people on these boards who have to deal with off-the-charts high pH, so the common advice to balance TA first doesn't apply to us, nor do the acid demand charts published on Doc's website or in the Taylor book. If your water comes from a limestone aquifer, it simply takes a bunch of acid to get the job done. If you have MPS, use it as a shock until you get the pH down. Its low pH will help out in the process. Ignore TA until you get the pH to stay in the range you want.
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I hate to tell you - your using too little chlorine!...
Great minds think alike, and small ones seldom differ! :) I started my post around the same time you did, but left to watch the news. When I finished and hit "post", I saw you had already covered a lot of the same ground. I could have saved some keystrokes!
I went over to Poolsearch and looked at some of the advice that is being given out there. I can understand why Tony chose to address his concerns here rather than jump into CapMorgan's thread over there. It reminded me of the Bizarro Superman comics of my youth. :o It is the first time I've seen the Vermonter approach described as "terrible, terrible". I don't know how much validity their theories have, but the two main proponents of liquid bleach certainly talk a good chemistry game (my head hurts just from following the discussion). The method described for balancing pH and TA had me envisioning standing over the tub like it is a witch's cauldron, adding chemicals, while turning aeration on and off, until presto, your water is balanced perfectly! :-?
Their positions on dichlor, CYA, and liquid bleach are certainly different than what you see in the Taylor materials, the guides on Doc's site, or any of the other info I have come across. I find it interesting that in their view, sodium hypochlorite is the gold standard and dichlor is to be used sparingly. They repeat the same chemistry primer in several posts/threads, blaming what are normally considered minimal CYA levels for reduced sanitizer efficiency. The things that concerned me based on sampling a few threads, is a seeming belief that simply switching to liquid bleach is the cure to most hot-tub problems (oversimplification on my part), although there was little concern for its affects on pH and TDS -- and that a pseudomonas infection is likely to occur if you don't follow thier approach. They do have some followers, but whenever I see testimonials to how simple something can be if you just follow a non-conventional approach, I wonder if they are "on to something, or on something". 8-)
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Reese, I got your PM. Thanks for the advice. My PM hasn't been working the last couple of days, so I had to post my reply here. :)
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When i shock my water i use 5 1/4 tsp which is 7 times my daily dose per Vermonter method and 24 later my chlorine level is still 10 ppm or higher i cant tell because my kit only goes to 10 ppm.
I will follow all of your advice, today i will dump half of my water, then i will get my PH in line at 7.5.
I will adjust my daily dosing to 1.5 tsp. Do i have to now adjust my shock level to 7 times that now, or leave it at 5 1/4 tsp since i can get a 10 ppm 24 hours later ?
CapMorgan
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When i shock my water i use 5 1/4 tsp which is 7 times my daily dose per Vermonter method and 24 later my chlorine level is still 10 ppm or higher i cant tell because my kit only goes to 10 ppm.
I will follow all of your advice, today i will dump half of my water, then i will get my PH in line at 7.5.
I will adjust my daily dosing to 1.5 tsp. Do i have to now adjust my shock level to 7 times that now, or leave it at 5 1/4 tsp since i can get a 10 ppm 24 hours later ?
CapMorgan
The 7 x your daily dose shock method is the only thing I don't do that Vermonter suggests. The only reason being, if I did I wouldn't be able to soak for a week due to the sky high FC. My daily dose is about 1 tsp for my 336 gallon tub and that will give me atleast a 3ppm 20 minutes after dosing.(when my water was new, I'd get a 5ppm). The most dichlor that I have added to my tub at one time(with a starting ppm of 0) was 4 tsp. That dose brought my FC to above 10(didn't know exactly b/c kit doesn't go that high) for two days. If I were to add 7 tsp I think I would be doing the decontamination process suggested in my owners manual, and I just don't think that would be neccessary every time I shock.
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Somewhere back in the archives is advice on how to find out what the level of dichlor is, even if it's "off the charts" high.
I believe it was by taking an equal amount of tub water and tap water, then using your kit or strip to test. Whatever the reading (say, 8ppm), double it to get a reasonable idea on how much you're dealing with. If you're STILL off the charts *gasp*, measure out more tap water, and multiply based on how much you've got....
Crude, but hopefully effective...
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When i shock my water i use 5 1/4 tsp which is 7 times my daily dose per Vermonter method and 24 later my chlorine level is still 10 ppm or higher i cant tell because my kit only goes to 10 ppm.
First let me say that I am by far no expert in this area. When shocking with dichlor you only need to add enough to get a FC reading of 10 x your CC. e.i.- if your CC is .5 you would only need a dose that would bring the FC to 5 in order to rid all the chloramines.
Do you test for CC ?
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What Reese said is true about the oils on your skin.
If your shocking with 10 PPM snd it stays then your chemically cleaning the tub with chlorine. There is a formula of when to change out the water - I think it's 2/3 the gallons of water divided by the # of days you've used the tub.
To test for high chlorine, use a non-chlorinated water and use a 50/50 mix and multiply the chlorine reading by2 ... if that's too high still use 2 parts non-chlorinated water to 1 part tub water and multiply by 3.
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To test for high chlorine, use a non-chlorinated water and use a 50/50 mix and multiply the chlorine reading by2 ... if that's too high still use 2 parts non-chlorinated water to 1 part tub water and multiply by 3.
Thanks for that Vinny. :) :) :) You're the best. 8-)
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I will follow all of your advice, today i will dump half of my water, then i will get my PH in line at 7.5.
I will adjust my daily dosing to 1.5 tsp. Do i have to now adjust my shock level to 7 times that now, or leave it at 5 1/4 tsp since i can get a 10 ppm 24 hours later ?
If your chlorine shocks persists for 24 hours, I doubt you have an infection in your tub, so the advice you got on the other forum about "hot tub itch" seems unfounded. I'm more concerned about your pH and the amount of time you are in water. I personally don't think you need to dump half your water yet, but if you are concerned about CYA, (I've asked the people over on Poolsearch for more info on that.) it won't hurt anything -- it will just require more acid to bring down the pH of the fresh water.
As far as your shock dose, the Vermonter rec of 7X your daily dose is only an approximation for those who don't measure CC. As WHY NOT said, you need to get to 10X CC, otherwise you are not accomplishing "breakpoint" which is necessary to reduce chloramines. An inadequate chlorine shock actually makes the problem worse! MPS is good alternative for you since it will help lower pH and CC measurement is not necessary, otherwise, stick with the 7X approximation.
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Reese, I got your PM. Thanks for the advice. My PM hasn't been working the last couple of days, so I had to post my reply here. :)
You are welcome. Now my PM is acting up. I couldn't respond to you there. BTW, I made a post on your chlorine question. Have a good day!:)
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After testing this morning, it appears my pH is in the 7.6 range. Alk in in the 50-70 range. I think I will give it a day to see what happens?
Then what , can I leave alk at that level if pH stays fairly stable?
Neo
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After testing this morning, it appears my pH is in the 7.6 range. Alk in in the 50-70 range. I think I will give it a day to see what happens?Then what , can I leave alk at that level if pH stays fairly stable?
Yes. If pH drifts down below 7.1, add sodium bicarb (baking soda) to raise it, that will bring up TA at the same time.
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Great minds think alike, and small ones seldom differ! :) I started my post around the same time you did, but left to watch the news. When I finished and hit "post", I saw you had already covered a lot of the same ground. I could have saved some keystrokes!
I went over to Poolsearch and looked at some of the advice that is being given out there. I can understand why Tony chose to address his concerns here rather than jump into CapMorgan's thread over there. It reminded me of the Bizarro Superman comics of my youth. :o It is the first time I've seen the Vermonter approach described as "terrible, terrible". I don't know how much validity their theories have, but the two main proponents of liquid bleach certainly talk a good chemistry game (my head hurts just from following the discussion). The method described for balancing pH and TA had me envisioning standing over the tub like it is a witch's cauldron, adding chemicals, while turning aeration on and off, until presto, your water is balanced perfectly! :-?
Their positions on dichlor, CYA, and liquid bleach are certainly different than what you see in the Taylor materials, the guides on Doc's site, or any of the other info I have come across. I find it interesting that in their view, sodium hypochlorite is the gold standard and dichlor is to be used sparingly. They repeat the same chemistry primer in several posts/threads, blaming what are normally considered minimal CYA levels for reduced sanitizer efficiency. The things that concerned me based on sampling a few threads, is a seeming belief that simply switching to liquid bleach is the cure to most hot-tub problems (oversimplification on my part), although there was little concern for its affects on pH and TDS -- and that a pseudomonas infection is likely to occur if you don't follow thier approach. They do have some followers, but whenever I see testimonials to how simple something can be if you just follow a non-conventional approach, I wonder if they are "on to something, or on something". 8-)
Reese,
Bleach works well in a pool and personally I balance out my water's parameters by using bleach, trichlor and cal hypo.
Sometimes free advice is truely worth nothing but honestly I have gotten bad advice from pool stores. CYA over 100 in my pool - 'that's great what are you worried about' - yeah right.
I am a firm believer of knowing what you need to do and not relying on some person telling me what to do. As newbies we can be swayed all over the place. Even on these forums I watched what was being said and believe some and discredit others.
When I was shopping for the tub I went into a D1 dealer and he was hawking the vision system (basically a N2 cartridge on steroids) without dichlor. When I mentioned that tubs need dichlor and I was planning on using dichlor after soaking (Vermonter's method), he told me how stupid that was because you need to use dichlor before you soak. Meanwhile he wanted $125 for the vision cartridge so I didn't need dichlor - but he told me I should use dichlor before soaking - :o
That's why I come and participate on this and Doc's forum ... hopefully my free advice over rides someone else's free advice and of course mine IS correct! 8-) ;) ;D
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Thanks Vinny and Reese for picking up on this. Not much more I can add. I agree with WHY NOT regarding shocking with MPS over Dichlor if you have concerns with CYA. Your weekly shock dose probably adds as much CYA as your daily dose over the long term, so using MPS could cut your CYA in half. I have switched to MPS because I don't have to wait to use my spa, it is a complete shock and idiot proof (if you use too little chlorine to shock...you haven't shocked) and last, it adds less to CYA.
As far as bleach is concerned, it works....but....it voids warranties, you have to watch your pH always because its going to rise quickly, you have to be very careful adding it and its shelf life is short. It is not for the faint of heart and not for the new user (anyone who tries bleach should be in full control of their chemistry and how to test it). As I said, I use it in my pool (as Vinny does) along with trichlor tabs where it makes sense because of the larger volume of water and because CYA is something that has to be addressed in an outdoor pool. I have experimented with bleach in my spa for a bit and quickly decided that the gains were very few, but the risks great. Dichlor is by far the best chlorine for a spa, IMO, just because it is pH neutral, is quick dissolving and is easy to use.
There was one suggestion from the other forum that experienced bromine users may want to experiment with. Shock weekly with bleach vs dichlor or MPS. The high pH of bleach helps neutralize the low pH of bromine.
BTW, there is a forum out there dedicated to sanitizing your POOL with bleach.
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Your weekly shock dose probably adds as much CYA as your daily dose over the long term, so using MPS could cut your CYA in half. I have switched to MPS because I don't have to wait to use my spa, it is a complete shock and idiot proof (if you use too little chlorine to shock...you haven't shocked) and last, it adds less to CYA.
Tony, I'm not sure exactly what CYA is. I test for it and know it's reccommended to keep it between 30-50 but that's about it. Can you explain exactly what it is and tell me why dichlor adds to it faster than mps?
Thanks.
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Why Not,
Here is some info for you on CYA
http://www.ppoa.org/pdfs/PrP_Cyanurics%20-%20Benefactor%20or%20Bomb.pdf
http://www.dsf.health.state.pa.us/health/cwp/view.asp?a=180&q=234664
CapMorgan
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Why Not,
Here is some info for you on CYA
http://www.ppoa.org/pdfs/PrP_Cyanurics%20-%20Benefactor%20or%20Bomb.pdf
http://www.dsf.health.state.pa.us/health/cwp/view.asp?a=180&q=234664
CapMorgan
Thanks for the links CapMorgan. I'm going back to school for a moment. Excuse me......
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Wow, thanks again for the links. I really do have a much better understanding of CYA. I think I finally found the culprit for my dichlor problems. I didn't know that dichlor is 57% CYA and that at a certain ppm, CYA actually starts to diminish the effects of chlorine. That explains why last month when my CYA was 40 I was getting much higher FC levels for a longer time opposed to this month with my CYA at 110.
I think it's time for a refill unless I feel like spending the extra money on dichlor. Times aren't that prosperous right now, so I better just dump it. :)
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To put in very simple terms, Cyanuric Acid (CYA) is like a series of little umbrellas that protect chlorine from the sun. In an outdoor pool, the sun will diminish the available chlorine rather quickly, thus the need for CYA (aka stabilizer). While chlorine will disappear from the water, CYA stays, something like TDS or calcium...the only way to dillute or eliminate is to change the water. Now that we know that these little umbrellas don't disappear, when there are too many of them, the chlorine becomes overprotected and has a more difficult time doing its job of sanitizing. In a pool, splashout, backwashing, etc help keep CYA levels down because you constantly add water. In a spa, periodic water changes solve the problem. You will find many articles regarding safe levels of CYA, but most public authorities recognize that 100 ppm should be max for a pool or spa.
In the small volume of water of a spa, all sanitizing methods have their good points and bad. There is no perfect sanitizer and there is no perfect chlorine.
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To put in very simple terms, Cyanuric Acid (CYA) is like a series of little umbrellas that protect chlorine from the sun. In an outdoor pool, the sun will diminish the available chlorine rather quickly, thus the need for CYA (aka stabilizer). While chlorine will disappear from the water, CYA stays, something like TDS or calcium...the only way to dillute or eliminate is to change the water. Now that we know that these little umbrellas don't disappear, when there are too many of them, the chlorine becomes overprotected and has a more difficult time doing its job of sanitizing. In a pool, splashout, backwashing, etc help keep CYA levels down because you constantly add water. In a spa, periodic water changes solve the problem. You will find many articles regarding safe levels of CYA, but most public authorities recognize that 100 ppm should be max for a pool or spa.
In the small volume of water of a spa, all sanitizing methods have their good points and bad. There is no perfect sanitizer and there is no perfect chlorine.
Well put. :D
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To put in very simple terms, Cyanuric Acid (CYA) is like a series of little umbrellas that protect chlorine from the sun. In an outdoor pool, the sun will diminish the available chlorine rather quickly, thus the need for CYA (aka stabilizer). While chlorine will disappear from the water, CYA stays, something like TDS or calcium...the only way to dillute or eliminate is to change the water. Now that we know that these little umbrellas don't disappear, when there are too many of them, the chlorine becomes overprotected and has a more difficult time doing its job of sanitizing. In a pool, splashout, backwashing, etc help keep CYA levels down because you constantly add water. In a spa, periodic water changes solve the problem. You will find many articles regarding safe levels of CYA, but most public authorities recognize that 100 ppm should be max for a pool or spa.
In the small volume of water of a spa, all sanitizing methods have their good points and bad. There is no perfect sanitizer and there is no perfect chlorine.
Very nice post. I wonder why a chemical manufacturer doesn't make a version of dichlor without CYA for spa users. I know Lithium Hypochlorite doesn't contain CYA but the available chlorine content is only 35%. Can't someone make 56% dichlor without CYA?