Re: tds bogus or true???????
Hi Steve,
Welcome to the forum (fancy meeting you here!)
I'm sure others will jump in but for the most part TDS is a bogus measurement. The discrepancies you saw were probably testing errors at the pool store or dealer who did the test. If you drain and refill they can sell you more chems faster! Since your spa should be drained and refilled about every 3 months (depending on bather load) it is NOT an important measurement at all!
Re: tds bogus or true???????
TDS is one of those things that is only important when you have eliminated all the typical issues and still have a problem. Phosphates is another.
If you cannot bring your pool under control using our main-line methods (adjusting pH, and T/A then hammering with bleach to keep at the shock level for the CYA level) THEN and only then do you turn to alternatives. First you check for metals, and then and only then do you bother exploring TDS or phosphates as the cause of your problems. (Note: TDS and phosphates are totally different issues).
But pool stores, not being familiar with the PoolForum methods push stuff that requires unnecessary, extreme and usually EXPENSIVE measures without checking for the tried and true problems and solutions.
99.9% of the time TDS is bogus. 1 time in a 1000 it's valid to explore it as the cause of your problems.
Re: tds bogus or true???????
Thank you waterbear. I'm hoping thru this forum I can find a system that will work for me in the tub. I was not sure how to start so I thought I would eliminate one quick theory. [ tds] carld you hit the nail right on the head. I do have a problem. It's called a 2"x3" nasty spot just above my left ankle.[ chem. burn] It is related to just our spa. I can swim in the pool with no problems. originally sodium dichloro-s-triazinetrione, dihydrate now were on the simple bbb system. As far as our spa we use a two step program with bromine. [Artic brand] Might as well start at the beginning. First got the tub I noticed some itching right off the bat at this location. Being a newbie our first fill of water did not take long for us to distroy. The itching continued even with new water. Was told tds were causing my problem. [ after multi. drains and refills the problem is still there and much worse] I'm convinced it's related to the bromine. Has anybody else experienced anything like this???? For the record nobody else is effected by the water not family or friends and only this one spot. I can climb in and soak with no problems except for this lone spot?????? We had a suggestion just to add the proper amount of sodium bromide at fillup and use bleach to shock??? Can we just change the water and go with the b,b,b, system without any bromine??? Maybe other options on what to use for a sanitizer???? The dealers have told me that using chlor. in the spa is much harsher than bromine???? suggestion, help,advice????? waterbear please chime in as we have had this conversation many times. steve Fyi:: I do hope someday this site has a hot tub/spa section.
Re: tds bogus or true???????
If you are the only one with this spot and you don't get it anywhere else - are you sure it's something caused by the spa and not some other skin infection that is aggravated by the spa- (staph or strep infection comes to mind). I am not a doctor - just logically wondering why it would only affect you and then only one part of your body.
Re: tds bogus or true???????
TRUE:
I've been a beachcomber hot tub, ( similar to arctic spas), owner for three years.
In my experience, yes TDS does matter.
When the TDS gets too high, your chemicals will not work as effectively, meaning you must use a lot more to effectively sanitize.
with conventional bromine or chlorine, after the sanitizer molecule burns up an organic particle, it turns into a bromamine or cloramine and thus leaves your hot tub with the cloudy, flat water ( if you have a lot of them... or high TDS).
it also can aid in making your hot tub have bad odor.
I'm not sure what the effect of a high TDS on your health might be...
( guess I should google it), but my guess would be that if your santizer isn't working as well then you leave yourself open for a multitude of possible health issues.
I would recommend taking your water to a different( brand) dealer of Hot Tubs for a free testing ( for comparrison purposes)...
I also suggest that you see your health professional.
( there is also a small possibility that you are allergic to bromine)
BTW, personally I prefer my "tub ride" at a TDS of about 800-1000... that's when everything just feels "right"... ( I find that "fresh water" doesn't bubble that well...lol)
The following is an article that I thought was interesting...
good luck with your tub :)
"TDS: Check it out when the water doesn't behave."
By David Dickman
Reprinted from Pool & Spa Service Industry News
TDS - Total Dissolved Solids - may be the most misunderstood factor in the whole field of pool & spa water chemistry. It is misunderstood because no one knows exactly what effect it is going to have on any particular body of water.
When everything else seems to be all right, and the water still acts screwy, check the TDS.
High TDS can result in corrosion of metal equipment and accessories, even though the water is balanced.
High TDS can cause eye and skin irritation, even though the pH is right and there are no chloramines in the water.
High TDS can permit an algae bloom, even with a 2-3 ppm chlorine residual.
But none of these symptoms will necessarily occur. It is the uncertain nature of problems caused by TDS that makes it such a headache to deal with.
As its name states, TDS is the sum total of all of the dissolved things in a given body of water. It's everything in the water that's not actually water. It includes hardness, alkalinity, cyanuric acid, chlorides, bromides, sulfates, silicates, and all manner of organic compounds.
Every time you add anything to the water, you are increasing its TDS. This includes not only sanitizing and pH adjusting chemicals, but also conditioner, algicides, and tile and surface cleaners. It includes airborne pollutants and bather waste as well as dissolved minerals in the fill water.
At low levels, TDS does not present a problem. In fact, a certain amount of TDS is necessary for water balance. Hardness and Total Alkalinity are both part of TDS.
But at high levels - above 3,000 parts per million - you are welcoming problems. The National Spa & Pool Institute, in its standards for both swimming pools and spas, recommends an ideal TDS of between 1,000 and 2,000 ppm, with a maximum of 3,000 ppm.
No one knows exactly what mechanism is at work when you're dealing with high TDS water. One commonly held theory is that when you get a lot of dissolved substances in water, they interfere with the normal workings of sanitizers. They may do this by forming a chemical "shield" around bacteria, algae, and other substances normally attacked by chlorine or bromine. Or they may simply present "roadblocks" in the path of sanitizer molecules, preventing them from freely circulating.
TDS buildup is inevitable. As we've explained, every time you add chemicals to water, you're increasing the TDS. When the water evaporates, it leaves behind all of the solids that had been dissolved in it.
Just how much are you increasing the TDS when you chemically treat pool or spa water? Well, for every pound of dry chemical that you add to a 15,000 gallon pool, you are increasing the TDS by about 8 ppm.
"Parts Per Million" is what scientists refer to as a "weight to weight" measurement. That is, if you know how much the water weighs, and you know how much the stuff you are adding to the water weighs, you can calculate how many parts per million you are adding to the water.
As it happens, one gallon of water weighs 8.34 pounds. So if you know how many gallons are in a pool or spa, and you multiply that number by 8.34, you will know how many pounds of water are in the pool or spa.
So, how many pounds of water are in a 450 gallon spa? The answer is 3,753 pounds (450 x 8.34 = 3,753). How about a 15,000 gallon pool? Well, 15,000 x 8.34 = 125,100. So, there are 125,100 pounds of water in a 15,000 gallon pool.
OK, so now you know how much the water weighs. Now, take 1 million and divide it by the total weight of that water, and you will find out how many parts per million are contained in each pound of water. For example, 1,000,000/125,100 (pounds of water in our 15,000 gallon pool) = 7.99. We'll call it 8. That is, every pound of material added to a 15,000 gallon pool will contribute about 8 parts per million.
How about our 450 gallon spa? Take 1,000,000, divide it by 3,753 (the weight of the water in the spa), and you get 266.45. We'll settle on 266. So for every pound of stuff that you add to a 450 gallon spa, you will be increasing the TDS by 266 parts per million.
Effect of Dissolved Material on TDS - Pools
(How Much 1 Pound of Material Will Raise TDS In Pools of Various Sizes)
Pool Capacity
TDS per 1 Pound
5,000 gal. 24 ppm
10,000 gal. 12 ppm
15,000 gal. 8 ppm
20,000 gal 6 ppm
25,000 gal 4.8 ppm
50,000 gal 2.4 ppm
100,000 gal 1.2 ppm
150,000 gal 0.8 ppm
Effect of Dissolved Material on TDS - Spas
(How Much 1 Pound of Material Will Raise TDS In Pools of Various Sizes)
Pool Capacity
TDS per 1 Pound
400 gal. 300 ppm
450 gal. 266 ppm
500 gal. 240 ppm
550 gal 218 ppm
600 gal 200 ppm
650 gal 184 ppm
700 gal 171 ppm
750 gal 160 ppm
The above charts should give you a pretty good idea of why TDS builds up so rapidly in spa water and also why the effect of chemical treatment is so dramatic when you are dealing with a spa. The accompanying charts - one for pools and the other for spas - will also give you an idea of how much of an impact 1 pound of chemical added to the water will have on TDS in vessels of different sizes.
Incidentally, if you wanted to design a pool that would contain almost exactly 1 million pounds of water, it would be a 120,000 gallon vessel. In that pool, every 1 pound of solids dissolved in the water would increase the TDS by 1 ppm.
Every sanitizing chemical, and every pH adjusting chemical used in the pool and spa industry will eventually contribute to the TDS in a pool or spa. Some will contribute more than others. Because sanitizing compounds often require the additonal use of pH adjusting chemicals, the chemical maintenance regimen you choose can have a dramatic effect on the buildup of TDS.
TDS is fairly easy to calculate for dry chemicals. It's a bit more complicated for liquid solutions. If a research lab were going to test the solids content of a liquid, they would take a precise volume of the liquid and then slowly heat it until the liquid itself had evaporated. Then they would dry the remaining solids and weight them.
The two most common liquid solutions used in our industry are muriatic acid and liquid chlorine (sodium hypochlorite). For your information, 1 gallon of muriatic acid will contribute 1.87 pounds of dissolved solids to the water. 1 gallon of liquid chlorine will contribute 2.2 pounds of dissolved solids.
You should also understand that every type of chlorine & sanitizer - including gas chlorine - eventually ends up contributing to TDS in the form of chloride. So every time you add a pound of dry chlorine compound, or infuse a pound of gas chlorine into a 15,000 gallon pool, you will wind up increasing the TDS by about 8 ppm.
TDS Testing
Short of a detailed laboratory analysis, the most dependable method of TDS testing is through the use of a portable TDS meter. These meters actually measure the conductivity of the water - its ability to conduct an electrical charge, which happens to increase as the TDS increases.
Hand-held TDS meters - usually in the $50.00 - $150.00 range, gggeenerally operate by either placing some water in a sample cell or dipping the meter directly in the pool water and pushing a button, which causes a small electric current to pass between two electrodes immersed in the water and separated by a specific distance.
The meter measures the current passing between the electrodes and uses that to deter mine the water's conductivity, the meter dial (or LCD readout) is calibrated to indicate TDS in parts per million.
The easieste way to reduce TDS is to drain the pool and refill it with fresh water. This can also be done in stages, taking the water level down 1 or 2 feet at a time and refilling over a period of days or weeks.
Under normal circumstances, pool water can be expected to last anywhere from 3 to 5 years before it has to be completely changed. Your choice of chemical treatment can help to determine just how long it lasts.
Re: tds bogus or true???????
First simmons99 you have a valid point. When the old doc has seen my leg it's been in full bloom and is in fact a serious chemical burn. I've just about got it cleared up maybe I'll go have it checked now. steve
Re: tds bogus or true???????
Regarding:
Quote:
Originally Posted by RavenNS
"TDS: Check it out when the water doesn't behave."
By David Dickman
Reprinted from Pool & Spa Service Industry News
:
:
:
This is an excellent presentation of confusing information. [EDIT] No offense to RavenNS -- I'm referring to the article reprint only [END-EDIT]. To lump all TDS together is ridiculous. A sea water pool which has 30,000 to 40,000 TDS operates just fine so obviously it's not just high TDS that is the issue. When the TDS is composed mostly of simple salts, especially sodium and chloride, then this is not a problem (it does change water balance slightly, due to ionic strength). Most of the chemicals you add to your pool add sodium or chloride either immediately or when they get used up or broken down (i.e. chlorine). Carbonates that get added to your pool (sodium bicarbonate or sodium carbonate) do not build up because they are always outgassing as carbon dioxide to the air.
On the other hand, organic material that gets into the pool and gets partly broken down by chlorine can sometimes stick around and not completely decompose. If the material is large enough, then it will get caught in the filter. If not, then it will remain dissolved. Now some of this organic material, if broken down into smaller molecules, can become food for bacteria and algae so that may explain why some higher TDS situations lead to what appears to be a reduction in sanitation or algae prevention (but is actually just that you don't have enough chlorine in the first place and were lucky that conditions for faster bacterial or algae growth weren't present). However, a conservative amount of chlorine (i.e. Ben's chart) should still work reliably in that environment. So while it may be true that a low TDS pool may be able to get away with a somewhat lower level of chlorine (below the minimums in Ben's chart, for example), I wouldn't say that a high TDS pool isn't manageable.
As for the smell of water that is high in TDS and has not been changed in a spa, that is most likely the result of incomplete oxidation of organics and resulting chloramines (if chlorine is used as a sanitizer or if used in conjunction with bromine). It would be interesting to find out if shocking a spa with high chlorine levels would take care of this problem.
In spite of what I just said, I think that regularly changing spa water makes a lot of sense since the quantity of organic material and bad stuff that gets put into the water is much, much larger per volume of water in a spa compared to a pool (even a commercial pool). If anyone has figured out how to maintain and shock such water so that they don't have to change it (or change it infrequently), then that would be useful information to know. As for pools, I believe they can go a lot longer without a water change, but in general you would end up doing some change of your pool water over time anyway through backwashing DE or sand filters. If you have a cartridge filter, then you probably have to manually drain and refill some pool water to refresh it periodically. In my own pool (which has a cartridge filter due to water restrictions in my area), I let each winter's rains effectively change about a third or so of the pool water (accounting for "continuous dilution").
Richard
Re: tds bogus or true???????
Sorry for the "sales pitch" but I mentioned that I would let you all know when a specific spa salt system was available...
AutoPilot has now introduced the Spa Pilot. Using 1500 ppm, it is designed to maintain a NON-USE chlorine residual for spas up to 800 gallons. It works in conjunction with "Power Pouches" that are added one pouch before and one after (potassium Monopersulfate and other propriatary ingredients).
Re: tds bogus or true???????
Poolsean, sounds like a winner to me! My spa is chlorinated by my SWG and it is really easy to maintain!
Re: tds bogus or true???????
RavenNS,
Since spas are drained and refilled every 1 to 3 months TDS is not an issue if they are properly maintained. The problem startes when people start dumping unnecessary defoamers, clairifies, fragrences, etc. into the water. Also, many people, including dealers, just don't understand bromine chemisty. Look at the number of people who just put bromine tabs in a floater and don't put sodum bromide in the water with each refill for an example and then wonder why they can't maintain a sanitizer level.....or the number of people who don't realize that chlorine is probably the most effective way to shock a bromine spa (or that almost all bromine tablets contain chlorine also for this reason!)
Re: tds bogus or true???????
Quote:
Originally Posted by Poolsean
Using 1500 ppm, it is designed to maintain a NON-USE chlorine residual for spas up to 800 gallons.
Sean,
Is the purpose of the chlorine primarily to regenerate bromide ion (Br-) back into hypobromous acid (HOBr) on a continual basis (which is what KMPS would do as well, though KMPS is also useful for oxidizing organics before chlorine does to prevent potentially smelly chloramine formation)? Or is it to also supplement the hypobromous acid for oxidation and disinfection? The "NON-USE" seems to imply that it is for the former, not the latter.
Richard
Re: tds bogus or true???????
First of all, Chem Geek, absolutely no offense taken... I didn't write the article, I just thought it was worth reading (especially for newbies to TDS).
regarding adding chlorine to bromine: I thought we ( waterbear & chemgeek & I) discussed this as a bad idea in another thread :p lol
I dump the tub water about every three or four months, although timing can be quite important in winter... no one wants to do the empty-refill maintance in a blizzard.
I do use quite a bit of chemicals for start-up ( not just throwing some pucks in). I also have two chemicals for cleaning the filters which I do every month.
not to mention " tub clean" a very acidic chemical that you run through prior to draining.. ( eat your skin off! & so stinky too)
My primary hot tub, although outdoors, is essentially an almost "closed system". The cover is always on, unless we are in it... ( steam doesn't even escape it in the coldest days of winter). It is a completely independant system & this may make it "behave" differently than waterbear's tub which is part of his pool system.
I don't "shock" my tub per say ( except for start-up), but I do bring the levels up quickly ( & probably in-fact shocking it); We often throw some "bromoblast" in the tub as we get into it. We actually prefer to keep our tub at 10+ppm; this really helps my DH with some troubling skin conditions that he used to take medication for, prior to getting the Tub.
( and if you have any pus sores, the high bromine seems to draw out the infection & help the healing process as it dries out the sore & seems to close it up too.... Also cures diaper rash! lol... & strips my hair of colour beautifully..:D )
As I said before I prefer the tub at a TDS of 800- 1000 ppm.I would be happy to just partially drain & refill, just to keep the TDS at that level.- I don't like the feel of high TDS water ( or low TDS water for that matter...lol). But I worry about the safety issues of residual bacteria living in the "pass-through" area of the motor/heater... ( I have a large amount of piping there... it may be like a tankless water heater, but it is several feet of piping)
( why is it difficult to believe that when there is tons of crap in your tub, or high TDS, that your sanitizer might get 'busy" with all that & that it won't be as effective? is it not plausibile?)
( also note that if you add fragrance for every tub-ride, you'll hit the high TDS mark very fast as well. & I suspect that the fragrance binding/bonding materials interfer somewhat with the sanitizers, although I have no proof of that. lol)
So maybe it isn't "important" if you are draining every three months... but for those people who don't; TDS monitoring is a good reminder of when to drain. :)
Re: tds bogus or true???????
Quote:
Originally Posted by RavenNS
( why is it difficult to believe that when there is tons of crap in your tub, or high TDS, that your sanitizer might get 'busy" with all that & that it won't be as effective? is it not plausibile?)
( also note that if you add fragrance for every tub-ride, you'll hit the high TDS mark very fast as well. & I suspect that the fragrance binding/bonding materials interfer somewhat with the sanitizers, although I have no proof of that. lol)
:)
Normally dissolved substances, specifically charged ions, in water only interfere with chemical reactions due to what is known as "ionic strength". With sufficiently high TDS, this does in fact start to shift equilibrium towards charged ionic species since their "activity" is reduced relative to their actual concentration. My spreadsheet actually calculates all of this. However, the effect is very small in terms of its effect on chlorine concentration (though not on LSI or water balance) and essentially can be ignored for the ranges of TDS we are dealing with. It would be very important in sea water, but even salt SWCG pools do not have enough TDS to be of concern.
As an example, in a pool without CYA and with 2 ppm chlorine, 7.5 pH, 100 TA, 300 CH, 510 TDS (the minimum with these other parameters), and a temperature of 80F, this results in 0.968 HOCl (now correctly interpreted in ppm Cl2 units as all chlorine is measured due to historical convention). If I increase the TDS to 3500, then the HOCl drops to 0.909 which isn't a huge change.
Interestingly, if I repeat the above with CYA of 30 ppm and use 3 ppm chlorine, then I get at 525 TDS (again, the minimum which is higher due to the CYA), 0.042 for HOCl. If I increase the TDS to 3500, then the HOCl drops to 0.041 which is hardly a change at all.
The reason that changes in TDS have virtually no effect on HOCl in the presence of CYA is that the CYA acts like a chlorine (specifially an HOCl) buffer and resists changes in HOCl level due to outside factors. Specifically, the dominant equation where CYA buffers HOCl has charged ions of equal strength (charge) on both sides of the equation so changes in ionic strength due to TDS mostly cancel each other out. Without CYA, it is the HOCl/OCl- relationship that is affected and here there is charge on one side of the equation and no charge on the other.
Now in spite of what I just said it is of course possible that some forms of organics that get into the water may behave somewhat like CYA and tie up the chlorine and reduce its effectiveness. However, any such substance would have to also report its chlorine in the standard chlorine test for FC and would have to not be destroyed (oxidized) by the chlorine. Chlorine bound to CYA gets reported as FC since it is released from CYA in a matter of seconds. So yes, it is possible for some other organic compounds to behave in a similar fashion, but most are simply 1) combined with chlorine and stay that way as "combined chlorine" until fully oxidized (and are measured as the CC part of TC, but are not in FC) or 2) are not affected by chlorine at all. Obviously CYA is an "organic substance" that inhibits chlorine so certainly it is possible for other substances to behave this way as well.
So again, it is not the high TDS in and of itself that is a problem, but rather the fact that a high TDS may indicate older water that has more organics in it (in addition to salt) and some of these organics may interfere with chlorine's effectiveness. My hunch, however, is that for most standard organics that get into the pool or spa, that few if any inhibit chlorine's effectiveness (assuming you do not allow combined chlorine to build up since obviously that is chlorine that is not effective).
Richard
Re: tds bogus or true???????
Quote:
Originally Posted by RavenNS
( why is it difficult to believe that when there is tons of crap in your tub, or high TDS, that your sanitizer might get 'busy" with all that & that it won't be as effective? is it not plausibile?)
I guess the reason I find that hard to believe is that every pool with an SWG is operating at or above the "limit" of 3000 ppm. Most SWGs recommend something in the neighborhood of 3000 ppm of salt alone and some are designed to work at 6000 ppm and even higher. I've yet to hear from anyone with an SWG who didnt rave about it.
Re: tds bogus or true???????
Richard,
It's primarily a chlorine generator but with additional NaCl and NaBr it can be a bromine generator. The "Non-Use" application means that the KMPS is used up front to create a residual for use, then to clean it up by oxidizing the combined chlorine (or combined bromine)...so actually, the latter.
Re: tds bogus or true???????
Quote:
Originally Posted by RavenNS
First of all, Chem Geek, absolutely no offense taken... I didn't write the article, I just thought it was worth reading (especially for newbies to TDS).
regarding adding chlorine to bromine: I thought we ( waterbear & chemgeek & I) discussed this as a bad idea in another thread :p lol
Wrong, I have stated many times that chlorine (read bleach) is probably the BEST oxidizer to use in a bromine system!
I dump the tub water about every three or four months, although timing can be quite important in winter... no one wants to do the empty-refill maintance in a blizzard.
I do use quite a bit of chemicals for start-up ( not just throwing some pucks in). I also have two chemicals for cleaning the filters which I do every month.
not to mention " tub clean" a very acidic chemical that you run through prior to draining.. ( eat your skin off! & so stinky too)
If you are so concerend about cleaning out the pipes I would suggest an enzyme product....they work great and are not toxic!
My primary hot tub, although outdoors, is essentially an almost "closed system". The cover is always on, unless we are in it... ( steam doesn't even escape it in the coldest days of winter). It is a completely independant system & this may make it "behave" differently than waterbear's tub which is part of his pool system.
I owned a portable hot tub for many years before I built my present pool/spa combo and kept it on both bromine and chlorine at different times.
I don't "shock" my tub per say ( except for start-up), but I do bring the levels up quickly ( & probably in-fact shocking it); We often throw some "bromoblast" in the tub as we get into it. We actually prefer to keep our tub at 10+ppm; this really helps my DH with some troubling skin conditions that he used to take medication for, prior to getting the Tub.
( and if you have any pus sores, the high bromine seems to draw out the infection & help the healing process as it dries out the sore & seems to close it up too.... Also cures diaper rash! lol... & strips my hair of colour beautifully..:D )
Shocking is really a misnomer for a bromine system. When you add the oxidizer, whether chlorine, MPS, or ozone it reacts with the bromine ions in the water to form hypobromous acid....your active sanitizer. Tabs contain both bromine and chlorine or bromine and MPS so as they dissolve they add both to the water. If your bromine levels are low try adding some bleach and watch them shoot up (if you have a bromine reserve in the water) if you don't believe me!
As I said before I prefer the tub at a TDS of 800- 1000 ppm.I would be happy to just partially drain & refill, just to keep the TDS at that level.- I don't like the feel of high TDS water ( or low TDS water for that matter...lol). But I worry about the safety issues of residual bacteria living in the "pass-through" area of the motor/heater... ( I have a large amount of piping there... it may be like a tankless water heater, but it is several feet of piping)
and has a constant flow of water with residual sanitizer passing through it whenever the filtration system is running!
( why is it difficult to believe that when there is tons of crap in your tub, or high TDS, that your sanitizer might get 'busy" with all that & that it won't be as effective? is it not plausibile?)
because there is no chemisty to back it up!
( also note that if you add fragrance for every tub-ride, you'll hit the high TDS mark very fast as well. & I suspect that the fragrance binding/bonding materials interfer somewhat with the sanitizers, although I have no proof of that. lol)
do you really need that crap in your tub? It just means that you will have to drain your tub more often....and the ingredients probably won't show up on a TDS test. That measure ions in the water...non ionic additions to the water won't register on the test!
So maybe it isn't "important" if you are draining every three months... but for those people who don't; TDS monitoring is a good reminder of when to drain. :)
With both pools and hot tubs there are certain maintenace rules to follow if you want trouble free performance. With hot tubs it means draining and refilling on a regular basis. A good indication that you need to do this is when the tub starts to foam or you see heavy scum starting to collect on the water line
Re: tds bogus or true???????
Okay, once again... I keep my tub at a minimum of 10ppm bromine. I do not need to shock as per industry standards in Canada.
I'm am not really worried about residual bacteria, it's just something that I think about because a family in my province was hospitalized due to that exact problem ( hot tub bacteria out of control & the kids almost died! - it was an indoor tub which was not properly sanatized prior to draining & clearly not sanatized properly when they refilled it months later... nasty bacteria was found in the piping by investigators).
I follow all the recommendations of my tub from the manufactor & have had perfect water in both of my tubs, always ( wish I could say that about my pool...lol).
( waterbear, I think you missed that I was being sarcastic in my last post..lol , sorry :) )
I don't put extra crap in my tub ( fragrances etc.), although I would love to scent my pool with Hawaiian Lily..lol, ( love that one; can't help but open a bottle & sniff it every week when I visit the hot tub store) ( btw, I have no intention of putting fragrance in my pool, okay? :p )
The question of this thread was asking if high TDS should be addressed & the tub dumped. It is my opinion that the answer is Yes.
It is only my personal opinion that a TDS of over 1450 in a hot tub, makes the water really yucky & not performing ( or feeling) as it should. Industry standards & tub manufactors concur with this opinion, however, chemists may or may not.
I further stated that I would keep my tub at 800- 1000 TDS ( if it were possible), as by my observations, that is when the water performs best ( for me & mine).
so again, the question of the postee was , should he dump his tub water?...
I still feel that he should have a second test done at another store & see what the levels are... if the TDS is high, I still believe he should drain & refill, regardless if the water is "fresh".
And since the postee had water trucked in, I would consider either going with a different water company, or asking them to check the TDS prior to delivering.... ( which makes me wonder if it could be picking up residual particles from not having the truck cleaned out throughly...)
( ps- I have never seen my tub start to foam or had scum-lines... maybe because of regular maitenance or maybe because I drain the tub when it reaches 1200 TDS...)
Re: tds bogus or true???????
Quote:
Originally Posted by RavenNS
Okay, once again... I keep my tub at a minimum of 10ppm bromine. I do not need to shock as per industry standards in Canada.
As I said before, shocking is NOT what is done with a bromine system. When you add oxidizer you are converting bromine ions back into hypobromous acid....whether this is done with chlorine, MPS, or ozone is moot. The action of the added oxidizer creates hypobromous acid from the bromine ions. If chlorine is used the hypochlorous acid is immediately converted into hypobromous acid. The effect of 'adding shock' to a hot tub (as it is commenly referred to) is to raise the bromine level in the water when it has dropped. Adding more bromine to the water will not accomplish this unless an oxidizer is also present. Basic bromine chemistry. If you use tabs in a floater then you are adding both bromine and clorine or bromine and MPS at the same time....depends on the tab you use whether it contains chlorine (most do) or MPS (only one brand that I am currently aware of)
I'm am not really worried about residual bacteria, it's just something that I think about because a family in my province was hospitalized due to that exact problem ( hot tub bacteria out of control & the kids almost died! - it was an indoor tub which was not properly sanatized prior to draining & clearly not sanatized properly when they refilled it months later... nasty bacteria was found in the piping by investigators).
This is why proper sanitation of a hot tub or pool IS so important...and why I don't like copper/silver systems that say you can use reduced chlorine levels or only MPS in a hot tub! With bromine levels of 10+ ppm your tub should be very well sanitized....I would worry about developing bromine sensitivity with that high a level, however....bromine is a known sensitizer and the biggest problem with it's use is that many people can get a reaction from it. Some exhibit this right away...others develop it over time with exposure to the bromine. Also, it seems that 'hot tub folliculitis' is more commen in bromine santized spas.
I follow all the recommendations of my tub from the manufactor & have had perfect water in both of my tubs, always ( wish I could say that about my pool...lol).
Hang around on the forum and you will find that your pool is actually EASIER to maintain then your hot tub....I speak from experience!
( waterbear, I think you missed that I was being sarcastic in my last post..lol , sorry :) )
I don't put extra crap in my tub ( fragrances etc.), although I would love to scent my pool with Hawaiian Lily..lol, ( love that one; can't help but open a bottle & sniff it every week when I visit the hot tub store) ( btw, I have no intention of putting fragrance in my pool, okay? :p )
The question of this thread was asking if high TDS should be addressed & the tub dumped. It is my opinion that the answer is Yes.
It is only my personal opinion that a TDS of over 1450 in a hot tub, makes the water really yucky & not performing ( or feeling) as it should. Industry standards & tub manufactors concur with this opinion, however, chemists may or may not.
I further stated that I would keep my tub at 800- 1000 TDS ( if it were possible), as by my observations, that is when the water performs best ( for me & mine).
so again, the question of the postee was , should he dump his tub water?...
I still feel that he should have a second test done at another store & see what the levels are... if the TDS is high, I still believe he should drain & refill, regardless if the water is "fresh".
He also said that he has the same water tested a few days later and the TDS was fine AND that the tub had just been filled....indicates a testing error. Also some places are using test strips to test for TDS....not very reliable. If you are maintaining your your tub properly and draining on a regular interval then the TDS test is not necessary.
And since the postee had water trucked in, I would consider either going with a different water company, or asking them to check the TDS prior to delivering.... ( which makes me wonder if it could be picking up residual particles from not having the truck cleaned out throughly...)
( ps- I have never seen my tub start to foam or had scum-lines... maybe because of regular maitenance or maybe because I drain the tub when it reaches 1200 TDS...)
Which I bet is around every 3 months or less. The effects of high TDS will be such things as foaming or scum. TDS is really only usefull as an approximation of how 'old the water is. There are hot tubs that are sanitized by SWGs so the TDS measurment for them will be totally useless since they will have a TDS of the salt level (usually around 3000ppm) plus whatever ionic solids are dissolved in the water such as calcium, magnesium , sodium , potassium, chloride, bromide, etc. In some reagions the fill water can have a TDS higher than the recommended levels and yet the tub or pool can be operated and maintained without any problems. In acutal practice TDS is about as useful a measurement as is the Langelier Saturation Index (which has been the topic of MANY discussions on here.
One final note....you stated that your hot tub is essentially a 'closed system'. You forgot the main thing that makes this assumption wrong....the bathers entering the tub. IF you never used it and no one ever got into the tub between each drain and refill then it would approximate a closed system much better. The first time someone enters the tub it stops being a closed system because of what the bather introduces into the water (sweat, fecal matter, body oils, etc)!
Re: tds bogus or true???????
For the reord. I would love to see test readings of 1000-1500. When we use to worry about the tds measement I'm talking 5000. Read second post. New water, only chems. needed, and two bathers. Test results 2500-5000. Yes there were strips used. First thing you say. strips are no good. We always take a pool sample with us too.[ 1250-1500 range. We go to the local pool store and also up to our artic dealer results close to the same with multi. test done each time. Our tub is sitting at 5000 right now. I dare you to fine cleaner, better smelling, and easier water to care of anywhere. no foam, no scum line nothing and we use no defoamers, scumballs,etc. As far as cleaning the tub I'm not sure how everybody else does it but we first run the cleaning product[ fresh start] for 24hrs. before dumping the water, dump the water, suck out all lines, flush with clean water all jets, filters,lines, etc. which fills the foot well and dump that water, suck lines, etc again, take our chlor. shock mixed wipe down all surfaces including the bottom of the cover and refill. We have had the same trucking compant bring us our water multi. times this year including 25" of water for the pool.[ 30' round] We have discovered that we have been adding sodium bromide to the water weekly. Could we be picking up a false reading because of over high levels of this???? steve
Re: tds bogus or true???????
Steve, that seems plausible to me ( that TDS is that high) given the early postings about salt water pools; but I'm not a chemist.
It would be interesting to see what TDS you'd have if you weren't using a sodium based bromine.
( I wouldn't necessarily conclude that the TDS readings were false, I could guess that they are really high because of heavy salt)
You certainly are giving your tub a thorough cleaning...lol
(I wonder : Could the sodium be the ingredient that is bothering your burn, more so than the bromine?)
Bromine usually helps skin conditions. not only did it help with the stuff that I mentioned before, but it helps with problems like psorisis too.
- of course, salt can help with many infections as well...
well, If you are happy with the tub water, then ignore the TDS ( as long as it doesn't void your warrenty)...
otherwise, switch to a regular bromine & drain every three to four months (depending on the TDS)
Good Luck :)
Re: tds bogus or true???????
Since he may see it here, I'm putting it here: "turbottt1" has been moved in to a 'banned' group, the "Bad Email Address" group, because his email address is dead. I use that group to prevent accidental emails from being sent to dead addresses, among other things. When emails bounce back to me, I automatically move users into that group. -Ben
Thank you for the cleaning adaboy.LOL! MY point to this thread is no one around here test with a meter. I've checked into them and wonder if this measement is worth the 350-400.00 investment in my own meter??? Thanks to the heads up by one of our members, I called and talked to one of the chemist who makes the product that we use. Thats when we discovered that it contains sodium bromide. As instructed weekly, I believe we have been overdosing on sodium bromide. Something we have been doing over the last 14 days is quite using our bromine and just using our shock [ 1oz.] after every use and once a week we shock with 3-4oz. Our taylor kit is not here yet, but our I believe oto[yellow] kit registers a level of between 3-5 ppm bromine. If I understand correctly with a two part system One part by itself does nothing and will not register on our kit. If my kit is showing 3-5ppm bromine than there must be bromine in the spa that our shock is reacting with???? I'm I correct??? steve
Re: tds bogus or true???????
Steve,
you are correct. ANY bromine based system needs sodium bromide in the water when the tub is initially filled. Tablets by themselves will NOT put enough bromine ions in the water to create a sufficient sanitizer level when the oxidiazer is added to the water for several weeks!
RavenNS, If sodium is the problems then Steve would get the same burns from either soft water or going into the ocean. I am sorry, but your theory does not 'hold water'....so to speak.
Once again I say TDS is a bogus measurement. In actual practice it means nothing. The main reason TDS came into use as a water parameter was NOT in bromine systems but in chlorine systems using stabilized chlorine. When trichlor and dichlor are used over a period of time TDS will rise (as it will with unstabilized chlorine) but so will the CYA (stabilziers). The vested intersts (manufacturers of stabilized chlorine and the pool stores that sell it) didn't want people to realize that the problems they were having with their pools was caused by the pools having too much CYA from continued use of stabilzied chlorine so TDS became the scapegoat and the reason they had to drain and refill. (Of course the problem is NOT our stabilzied chlorine tabs that you are using...its the TDS in the water! Your CYA level of 200 ppm is not the reason your chorine is not keeping the algae out of your pool...it's the TDS of 3000 ppm. It's not the high CYA that is causing the pitting of your plaster finish....it's the high TDS.:rolleyes:) EVERY problems attributed to high TDS is KNOWN to be caused by overstabilization yet pools that have very high TDS (sometimes in excess of 6000 ppm) but are not overstabilized exhibit NONE of these problems....every pool with a SWG is a prime example!
Now if you would care to discuss the Langelier Saturation index (another bogus measurement)...:rolleyes:
Also, bromine is a known sensitizer and many people have reactions from it. That is one of it's big downsides. I would like to know where you got the information that bromine helps skin coditions? If it is from the antibacterial effect then chlorine is equaly effective. In fact, chlorine is a more effective sanitizer than bromine. A FC level of 3 ppm is equivalent to a bromine level of 6.75 ppm!
Re: tds bogus or true???????
I would just like to respond to the earlier question about getting a TDS meter for home use. I suspect this isn't a great idea, though it's probably easier to get a reliable and relatively inexpensive TDS meter than it is to get an ORP sensor. TDS is most often measured by conductivity. This has several problems, however. First of all, it doesn't measure anything that isn't charged, so neutral dissolved solids aren't measured. Second, you have to plug in numbers into formulas for roughly what is already known to be in the water (CH, TA, etc.) since the conductivity measurement doesn't tell you the "weight" of the solid and "ppm" is a weight measurement. Finally, conductivity measurements are affected by the size of the charge, so an ion with a charge of 2 registers 4 times as much as an ion with a charge of 1 (a charge of 3 registers 9 times -- yes, it's the square of the charge that gets measured) so if you don't know what's in your water composing TDS, you're measurement will be bogus (probably too high).
So, bottom line, to the degree you already know a lot about what is in your pool or spa, then you have a chance of figuring out your TDS. The fact is that you can probably add it up yourself from the CH, TA, CYA, and salt (NaCl) (and maybe borates/boric acid if you use Borax). If you stick with BBB, then you won't have other junk including sulfates in your pool. Now with a hot tub that's using bromine and fragrances and all this other stuff, I personally think it's just better to change the water frequently regardless of TDS. As waterbear says, TDS is not particularly useful to know as a single total number -- it's the components that are important and there is no way of knowing if extra junk causing high TDS is a problem or not. If it's just plain salt, it's clearly not a problem.
I have TDS in my spreadsheet and it influences the boo-hoo'd saturation index (it's not so much that it's bogus, but that it's over-emphasized and I've improved upon it anyway:cool: ), but what is more useful is to know how much specific chloride ion there is, and sulfates, etc. since these influence things such as chlorine outgassing that are much more relevant and useful (though very hard to predict with accuracy).
Consider the following. If we can figure out why the pH rises in so many pools (both SWCG and non-SWCG) and can come up with something simple like keeping TA at 80 or 60 or something like that, then that will save a LOT on chemicals (acid) and will help keep down TDS as well.
Bottom line, save your money and try to focus on keeping things simple. Using BBB will significantly reduce the extra stuff that is in most pools -- clarifiers, KMPS shock (lots and lots of sulfate in that one), defoamers, enzymatic cleansers, sequestering agents, algicide, etc. etc.
Richard
