chem geek
-
Posts
5,297 -
Joined
-
Last visited
-
Days Won
1
Posts posted by chem geek
-
-
If your goal is just to minimize the chlorine level, and again you need to stop thinking about FC as that level since it is not (it's the FC/CYA ratio that is relevant), then you can use other means to control algae and then have a lower FC/CYA ratio. While copper will control algae, it can also stain plaster surfaces and turn blond hair greenish so I wouldn't use it if you have a plaster pool or if people with blond hair use the pool. You could instead use a phosphate remover that would accomplish the same thing for algae control.
So if you want a lower active chlorine level with these supplemental products preventing algae growth, then target around 2-3% for your FC/CYA ratio. You should set your CYA level high enough so that you don't use up too much chlorine during the day. So that means 1 to 1.5 ppm FC with 50 ppm CYA, for example. It makes absolutely no sense at all to try and keep the FC at 0.5 ppm -- again, FC is meaningless and only tells you the RESERVE of chlorine, NOT the active amount of chlorine that reacts with swimsuits, skin, and hair. If you go too far, say to 0.5 ppm FC with 100 ppm CYA, then you will not only have so little reserve that it could get to zero too easily, but the active chlorine level will be low enough for some pathogens to grow and possibly biofilms to form. You don't want to push it too far.
And you are wrong about (only) Europe using hydrogen peroxide. DIN 19643 which is the German standard used in many countries in Europe for commercial/public pools uses chlorine, NOT hydrogen peroxide. In Europe, just as in the U.S., you can do whatever you want in your own private pool just like you can leave a chicken out on the counter for hours and then cut vegetables in its juices and the government isn't going to do anything about it. In a commercial kitchen, however, there are rules for preventing people from getting sick just as there are for commercial/public pools. So this idea that hydrogen peroxide is used (only) in Europe is simply baloney -- it is used in the U.S. along with other "alternatives" in private pools such as metal ion systems (by themselves such as Pristine Blue), enzymes (e.g. ClearChoice), surfactant biofilm removal systems (e.g. Aquafinesse), etc. The only thing about the U.S. (and Canada) is that these alternatives cannot claim to be disinfectants. Some of these companies, particularly those promoting metal ion systems, got into trouble with the EPA and now have to qualify their bactericidal claims with "*Nonpublic Health Bacteria".
By the way, the DIN 19643 standard uses 0.3 to 0.6 ppm FC but with no CYA and with ozone it's 0.2 to 0.5 ppm FC. The 2%-3% FC/CYA ratio I'm saying you could do if you had supplemental algae prevention has the same active chlorine level as around 0.01 ppm FC with no CYA so extraordinarily low. There's no way commercial/public pools would go for this because they want to have a certain minimum kill rate of pathogens to prevent person-to-person transmission of disease and they need higher levels of oxidation due to higher bather loads (and most such pools don't have supplemental oxidation systems), but in a residential pool that risk is very low. Also, the systems used with DIN 19643 to maintain low chlorine levels are very high end with fast turnovers and very responsive dosing systems. You don't have anything like that in your own pool which is why you probably should not try and go below 1 ppm FC even if you had lower CYA levels (which you wouldn't since you want a lower active chlorine level so lower FC/CYA ratio).
-
It used to be one of the "pinned" articles but I no longer see it here. You can see the same article on another forum here.
Yes, you should use Ahh-Some for cleaning your spa before doing a water change. For a new spa, fill it with water (at least enough to reach the jets), use the Ahh-Some, then dump. It will remove a LOT of gunk that is in new spas and your water will last longer by doing so.
-
If the intent is to have more oxidation, then yes having metal ions plus hydrogen peroxide will result in hydroxyl radicals, at least when iron is used. If you read the paper I linked to, when copper is used there aren't many hydroxyl radicals produced, at least at a pH of 8.0 (there may be more produced at lower pH). Instead with copper it's superoxide anion (O2•-) which is not as powerful an oxidizer as hydroxyl radical (OH•). So if you are going to want a Fenton reaction, you'd use iron instead of copper. Of course, if you want hydroxyl radicals, there are other ways of getting those including use of ozone that decays in part to hydroxyl radicals or use of boron-doped diamond electrodes with electrolysis or the use of titanium dioxide in the water.
By the way, when the UV in sunlight breaks down chlorine, it produces hydroxyl radicals (see this post). So with chlorine you get the best of both worlds -- you get very fast disinfection from hypochlorous acid (HOCl) and you get some hydroxyl radicals in outdoor pools. This is one reason why it's fairly easy to have very low active chlorine levels in outdoor residential pools and keep them very clean and clear with minimal combined chlorine and little buildup of organics. It's not enough to handle higher bather loads as with commercial/public pools so there supplemental oxidation systems (such as ozone) can be used to reduce the production of chlorinated disinfection by-products.
As for hydrogen peroxide and chlorine, these also react with each other and in fact hydrogen peroxide is an easy way to reduce chlorine levels. The link you gave was not a combination of these but rather SEQUENTIAL application of first sodium hypochlorite and then hydrogen peroxide with copper sulfate. It took lower levels of each when used in this sequential combination, mostly because of the one-two punch for killing via different mechanisms that prevent the organism from inhibiting just one of these chemicals. The pathogen in question was not a human one but a fungus on citrus.
Copper by itself does not contribute to chlorine decay in dilute solutions as found in pools. Metal ions in general do catalyze decay of concentrated hypochlorite solutions (i.e. chlorinating liquid or bleach) where they specifically catalyze the decomposition pathway of hypochlorite to oxygen gas. The usual decomposition pathway without such metal ion catalysts is to chloride and chlorate.
It sounds like you are trying to use something other than chlorine for disinfection (and oxidation). Why are you trying to do that? Do you realize that with Cyanuric Acid in the water and with the Free Chlorine set to prevent algae growth regardless of algae nutrient (phosphate and nitrate) level (so an FC/CYA ratio of 7.5%) that the active chlorine level is the same as with an FC of only 0.06 ppm with no CYA? Why would you want to try and eliminate such a low level of chlorine when it is incredibly effective against human pathogens as well as in preventing algae growth?
-
Both copper and iron metal ions are incompatible with hydrogen peroxide because of Fenton-like reactions. For copper, this is described in this paper. Basically, the metal ions catalyze hydrogen peroxide destruction to oxygen gas and water. This paper goes into detail for the Fenton reaction when iron ions are present.
Hydrogen peroxide is not a great biocide for pools and spas. You need the concentration to be at a rather high level of 100 ppm to have fast enough kill times for some bacteria (still not enough for others), but at that level it can also be irritating. See this paper showing hydrogen peroxide not to be effective in swimming pools and this paper explaining why some bacteria are not killed by hydrogen peroxide and this paper that showed some killing when combining hydrogen peroxide and silver ions, but still too slow for some pathogens unless the hydrogen peroxide concentration were 30,000 ppm which is way too high. See also this thread and this thread both describing damage to hot tub components when using hydrogen peroxide.
-
OK, then for every 10 ppm Free Chlorine (FC) added by Dichlor, it also increases Cyanuric Acid (CYA) by 9 ppm. 8 pounds of Dichlor in 22,000 gallons would be 24 ppm FC and 22 ppm CYA. 16 pounds would be double that. You can use PoolMath for calculating dosages and the effects of chemicals.
So you can keep using Dichlor until you get to a CYA of 80 ppm, but you should target your FC level to be at least 7.5% of the CYA level in order to prevent algae growth regardless of algae nutrient level. If your CYA gets to 80 ppm before the 30 days are up, salt added, and SWG turned on, then switch to using chlorinating liquid or bleach. You should read Water Balance for SWGs in the Pool School before you switch over so that you can prepare your pool so that it will have less pH rise. Basically, you want to get your TA lowered to around 60 or 70 ppm. You'll target a pH probably around 7.7 and you'll add enough calcium to get the CH so that the saturation index is only slightly negative (-0.2 or -0.1). You can optionally then add 50 ppm Borates to the pool.
-
What kind of granular chlorine are you using? Is it Cal-Hypo, Trichlor granular, or Dichlor? They each add more than chlorine so it's good to know so you aren't surprised. Also, have you added any Cyanuric Acid (CYA) to the water yet or are you waiting on that as well?
-
Since the ascorbic acid worked, you can use that to remove the stain. Then you need to decide what to do next. Use a metal sequestrant product (HEDP-based -- see some recommendations in the Pool School) both initially and with a weekly maintenance dose OR use a product like Metal Magic that tries to coagulate with the metal to get caught in the filter OR use CuLator in the skimmer to physically remove the metal from the water OR do water replacement to remove the metal. You'll need to compare costs of each approach to decide what's best since in some places water replacement is least expensive while in others the water is more expensive (or scarce).
-
If you maintain an FC level that is appropriate for your CYA level, then you shouldn't need algaecide, clarifiers, flocculants, shocking, or any other products. Just chlorinating liquid or bleach (once other pool water chemistry parameters are in balance) and a small amount of acid. Read the Pool School for further info.
If you insist on using an algaecide because you want to use Trichlor tabs, then Polyquat 60 algaecide would be better, but needs to be added weekly. Another option is to use a phosphate remover but that can get expensive. The problem is continued use of Trichlor tabs as your sole source of chlorine. For every 10 ppm Free Chlorine (FC) added by Trichlor, it also increases Cyanuric Acid (CYA) by 6 ppm.
-
Yes, if you remove the stain so that the metal is in the water and then you replace the water with fill water free in metals, then you won't need to continue to use metal sequestrant and shouldn't need to test for metal again.
Most likely the product a pool store had you add was an algaecide that had copper in it. I don't think there's any pool store product that adds iron. However, ascorbic acid usually removes iron stains best; it's citric acid that removes copper stains. So your experience is a little off though it's still possible you had a copper stain that was removed by your ascorbic acid treatment, especially since it was only on vinyl and not plaster.
-
I forgot to mention that the K-2006 does not have a salt test so you'd need to get either AquaChek Salt Test Strips or the Taylor K-1766.
The ozone from the ozone generator will react with the chlorine to produce oxygen gas and chloride ion. Though inefficient, there should be enough of each on their own to keep the spa in good shape. If you are able to time them to not run at the same time, then that would obviously be better. Probably running the ozone right after the high usage for an hour or two and then run the chlorine after that and for background dosing in between soaks would be best.
-
I see you now got into TFP with this thread so it's best you get taken care of there.
The 80 ppm FC will not be a problem for the liner because you aren't raising the chlorine that high. You are adding it incrementally and cumulatively. The chlorine will get used up combining with ammonia to form monochloramine and then will oxidize the monochloramine to nitrogen gas, nitrate, and chloride.
Always add concentrated chemicals slowly over a return flow in the deep end of the pool with the pump running and right after adding the chemical brush the side and bottom of the pool where you've added the chemical to ensure thorough mixing.
I see you were able to post to TFP so you should continue the discussion over there.
-
Do a Google search of "Bio-Active CYA site:www.troublefreepool.com" and you will see many threads showing that the Bio-Active product mostly does not work. There have been only two cases where it seemed to work at least some but nearly a dozen cases where it didn't seem to work at all.
A partial drain/refill is a more reliable way to reduce CYA. However, if you don't have your own good test kit, such as the Taylor K-2006, then you really don't know what your CYA level actually is. Most pool stores don't perform that test correctly (or others tests either).
It is true that Trichlor pucks increase the CYA level. For every 10 ppm Free Chlorine (FC) added by Trichlor, it also increases Cyanuric Acid (CYA) by 6 ppm. It is also true that Trichlor pucks are acidic and will consume TA if you don't add any and that the pH can crash if the TA gets exhausted.
The Leslie's guy is lying about their Trichlor tabs somehow not increasing CYA. That's baloney. ALL Trichlor increases CYA -- it's part of the Trichlor chemical!
I suggest you start reading the Pool School to learn how to take charge of your pool, starting with a proper test kit.
-
Did you get banned from TFP? Anyone is able to register at TFP -- did you not wait long enough for someone to let you register (they check each person to make sure they aren't a spammer)? You mention Ben, but Ben Powell is at The Pool Forum (or was), not Trouble Free Pool. So I'm confused by what you wrote.
It sounds like you had a bacterial conversion of CYA into ammonia. That takes a LOT of chlorine to get rid of that ammonia. You can get a rough estimate based on how much CYA was lost since it takes roughly 2-1/2 times that CYA loss as FC cumulatively added worst case. You can also get an ammonia test kit to see how much ammonia you have, but usually there is also partially degraded CYA that won't show up in the ammonia test. Your bucket test gives you an estimate of how much chlorine you need to add and the ammonia test you did is consistent with that (roughly 80 ppm FC or so). You can add it in 20 ppm FC increments, then measuring to see if FC is holding. Once FC holds some but still may drop, add enough to maintain 10 ppm FC if your CYA is 0. Once you are holding FC for at least a little while, you can start adding some CYA.
-
Not a surprise that pool companies or pool stores get different testing results. This is why we say you should always use your own good test kit, preferably the Taylor K-2006 as you are using.
The higher CC isn't good. Are you using Trichlor pucks as your source of chlorine? For every 10 ppm Free Chlorine (FC) added by Trichlor, it also increases Cyanuric Acid (CYA) by 6 ppm. Your FC is too low for your CYA level. The FC should be at least 7.5% of the CYA level in a manually dosed pool (i.e. not a saltwater chlorine generator pool). See the Chlorine / CYA Chart that shows you should have a minimum of 5 ppm FC if you want to prevent green and black algae growth regardless of algae nutrient (phosphate and nitrate) level.
You need to SLAM your pool using chlorinating liquid or bleach. See SLAM - Shock Level and Maintain. That will kill off nascent algae growth and likely get rid of the CC as well. You need to keep your pool uncovered and exposed to sunlight since the UV in sunlight will help in several ways. Then after you are done with the SLAM, you need to maintain the proper FC/CYA levels and if you continue to use Trichlor then your CYA level will continue to climb so you should consider using chlorinating liquid or bleach as your primary source of chlorine. Unfortunately, that means buying and hauling the heavier chlorine (since it's mostly water) and adding it every day or two to the pool unless you have a pool cover in which case you may be able to add chlorine twice a week instead. See the Pool School for more info on how to properly manage your pool.
-
I can't comment on what is now currently being sold in Australia, but in the U.S. where 3000 ppm salt levels are typically used (in Australia it's more common to have 5000 ppm salt) the main brands are reasonably reliable and not too expensive. As shown in this thread, the cells now last roughly 10,000 hours if well maintained and systems cost less than $1000.
The issue you bring up is whether automation that also does acid dosing is required. Instead of that, why don't you just operate the pool in a way that minimizes the amount of acid needed in the first place? See Water Balance for SWGs where a higher Cyanuric Acid (CYA aka stabilizer or conditioner) level of 80 ppm should let you cut down your % on-time while a lower Total Alkalinity (TA) no higher than 70 ppm and a higher pH target of around 7.8 should reduce carbon dioxide outgassing which causes pH to rise. Finally, you can optionally use 50 ppm Borates (usually from boric acid though it can also be added from borax and acid) as a pH buffer to make any acid additions less frequent.
-
Well a roughly 50% loss over roughly 24 hours is higher than normal, but at least it's holding chlorine and is better than before. You can see how things go from here.
There isn't much point measuring after a soak. Chlorine will get used up during a soak. What you want to do is measure before your soak, add chlorine afterwards, then measure again before the next soak or 24 hours later, whichever comes first. You want to add enough chlorine after your soak so that you still measure a residual of chlorine 24 hours later. Usually people want to start their soak with 1-2 ppm FC, but until you get a better handle on your chlorine usage you might target somewhat higher.
You should not need to shock if you add chlorine regularly with the Dichlor-then-bleach method. Again, that might be something old in Nitro's thread.
-
This is a duplicate of this thread where this question has already been answered.
-
Thanks for keeping us posted, but it's still very mysterious. This MSDS for SpaGuard Oxidizer Spa Lite says it contains Dichlor, aluminum sulfate, and a boron salt. I wonder if the boron salt is sodium tetraborate pentahydrate (similar to Borax). If so, then that raises the pH and may be in there to counteract the Dichlor. Maybe you should stop using that chemical and see if this makes a difference.
As for bromine concentrate, what specific brand and name of product are you using? Maybe it too has a base that would cause the pH to rise or the product to not be as net acidic as it would normally be.
-
(deleted duplicate post)
-
This was already answered in this thread that appears to be a duplicate of this one.
-
You calculated correctly, but maybe they are wrong in their calculation. Was the product Rendezvous Liquid Calcium Hardness Up? If so, it says 1 ounce in 500 gallons raises CH by 7 ppm. So 8 ounces would raise CH by 56 ppm. So 3 times that would be 168 ppm CH.
There won't be any borates in the fill water so yes assume 0 to start and dose to get to 50 ppm, but use boric acid since it's easier than adding borax and acid. You can get boric acid at Duda Diesel or The Chemistry Store.
The TA in those pages is wrong and should say 50 ppm. Unfortunately, Nitro is not around here anymore to update it and only he (or an admin, I suppose) can change it. The TA needs to be lower and borates are not optional in order to have the pH be more stable when there is aeration.
-
Yes, the Onzen system is a saltwater chlorine generator so the K-2006 would work well with such a system. Don't forget to add some Cyanuric Acid (CYA) to the water or else the chlorine will be too strong. About 30-40 ppm CYA should work well.
-
It does seem like one treatment with Ahh-Some in your case was enough and that there wasn't a need to superchlorinate. If your chlorine demand starts out fairly normal in the spa, then you'll know it's OK.
Do you have an ozonator? With no ozonator, you should find your 24-hour chlorine demand to be a 25% or lower loss in FC assuming your spa water stays warm/hot. With an ozonator, you may find that the loss is 50% or more because ozone reacts with chlorine to form chloride and chlorate salts.
Are you sure you added 20 ounces of calcium hardness increaser to your 410 gallon tub? That's way too much. Where did you get to add that much? Exactly how much to add depends on the product. With calcium chloride anhydrous 20 ounces weight (around 16 ounces volume) would raise the CH by 330 ppm while calcium chloride dihydrate would raise it by 250 ppm. So the product you used must be cut to be less pure, but even so...
If you accurately dose, you shouldn't need to test for borates since you replace them on every water change and there aren't any in tap water.
Your target TA should be 50 ppm, not 80 ppm. A lower TA will have less of a pH rise over time. The sticky may be wrong about that if it still says 80 ppm for TA. If you find your pH is stable at your 70 ppm TA, then you can just leave it since the initial use of Dichlor over time will lower the TA by about another 10 ppm. Worst case your adding acid to maintain pH will also lower the TA.
Yes, your chlorine demand is over 25% since it lost a little more than that just overnight. I'd just wait to see how it goes. There may just be a little leftover that chlorine is oxidizing OR you have an ozonator (do you have an ozonator?). If you have an ozonator, then that may explain the higher loss and that unfortunately will make it harder to maintain chlorine in the spa, though not impossible if you use it every day or two. You'll just need to dose high enough so that you still have a 1-2 ppm FC residual at the start of your next soak.
-
The non-chlorine shock (MPS) is an oxidizer, not a disinfectant (unless used in conjunction with silver ions in the Nature2 system). So you can use it as an expensive supplement for oxidation, at least until you use it up.
You do not need a separate enzyme cleaner. Ahh-Some is all you need at most once per water change.
Yes, those are the four primary methods, but there is also Nature2 (silver ions) with MPS. There are variants of chlorine and bromine systems by various manufacturers using cartridges (e.g. Frog for bromine). There is also Baquacil/Biguanide/PHMB but that is not as common and is expensive.
How did you calculate changing the water every 68 days? If you are using the "standard" Water Replacement Interval (WRI) formula that is (1/3) x (Spa Size in Gallons) / (# of persons per day), that assumes fairly short soaks of 20 minutes. So I presume you used that formula for 2 people. That would be roughly the time when using Dichlor-only. If you were to use Dichlor-then-bleach, you'd get roughly double (or more) the time between water changes. This is because you would avoid the CYA buildup from Dichlor that makes the chlorine less effective over time to the point where it oxidizes bather waste more slowly than you are adding it via usage so the water gets dull/cloudy. Note that if you are using the spa for more than 20 minutes, then you will need to change the water more frequently. Use "1/9" as a factor for Dichlor-only if you use "person-hours" in the denominator. Use "2/9" as the factor for Dichlor-then-bleach with person-hours. These are just rough estimates and you can change the water whenever you feel it is no longer fresh and clear.
The bromine methods still require adding some oxidizer after each soak unless you crank up your bromine tab output and you soak regularly and don't mind starting out with higher bromine levels during a soak.
I should point out that there are also automatic chlorine dosing methods such as using the ControlOMatic Technichlor saltwater chlorine generator. Even with this system, you may need to dose after a soak if you want to be able to start out the soak with a low 1-2 ppm FC chlorine level and just have the generator handle background dosing in between soaks.
Why Is Copper Sulfate Incompatible With Hydrogen Peroxide?
in Swimming Pool Water Chemistry
Posted
If you don't use any CYA at all, not even adding pure CYA initially, then the chlorine will be MUCH too strong and also it will break down MUCH too quickly in sunlight, losing roughly half every hour in direct noontime sun. CYA significantly moderates chlorine's strength and that's a GOOD thing if done in moderation.
I think you still aren't understanding how CYA moderates chlorine's strength. It's not just a little. When I wrote that you would have 0.01 ppm FC with no CYA equivalent of active chlorine in the pool when you have 2-3% FC/CYA ratio, I meant it. So for you to think that you could have 0.5 ppm FC with no CYA in the pool as being OK is strange since that is 50 times higher in active chlorine that oxidizes swimsuits, skin, and hair and produces chlorinated disinfection by-products. FIFTY TIMES!
If you maintained an FC/CYA ratio of 7.5%, then you wouldn't need to use any algae prevention supplements at all, no copper or algaecide needed of any kind. It's up to you which way to go, but you definitely want to use some CYA in the water if you're using chlorine.