Jump to content


  • Posts

  • Joined

  • Last visited

Everything posted by quantumchromodynamics

  1. The people who wrote the manual do not understand that bicarbonate causes pH rise. HCO3- < > CO2(aq) + OH- bicarbonate < > dissolved carbon dioxide + hydroxide ion or HCO3- + H+ < > CO2(aq) + H2O Bicarbonate + hydrogen ion < > dissolved carbon dioxide + water As you add bicarbonate, you reduce the hydrogen ion concentration and increase the hydroxide ion concentration. This is what causes the pH to rise. Since the bicarbonate is in equilibrium with the carbon dioxide, a change in one affects the other. If you cause the carbon dioxide to come out of solution and off-gas, it will shift the equilibrium to the right and bicarbonate will become carbon dioxide, which will raise the pH. The two main ways to force carbon dioxide to come out of solution and off-gas are heating the water and aeration. Aeration is just agitating the water by running the pumps and blowers. The key to finding the right TA is if your pH is consistently too high, then your TA is too high. If your pH is consistently too low, then your TA is too low. When your TA is right, your pH will remain where you want it to with very little effort. Forget about trying to make your TA fit into any range. Let it go wherever it needs to to achieve pH stability. You can use regular, unscented 6 % bleach (sodium hypochlorite) to shock. Make sure that you do not get any sort of "special" bleach, such as scented or "splashless".. Make sure that it says "Sodium Hypochlorite...6.0 %" on the label. You will have to determine the correct amount based on your testing. 0.37 ounce (volume) of 6.0 % bleach will increase bromine by 1.0 ppm in 400 gallons of water. MPS will oxidize bromide to bromine. To calculate the hardness of your water, you can use the pool calculator. It calculates the CSI (Calcite Saturation Index). Be sure to fill in all of the boxes including temperature to get an accurate CSI calculation. If you haven't done a decontamination procedure, you might want to consider doing it and starting over.
  2. It's in there. Since it's a pdf, you can use the "find" box. Enter DMH in the find box. It's on page 3. Reference That's partly my point. The 200 ppm limit suggests that there is a similar relationship between bromine and DMH as there is with chlorine and cyanuric acid. Without knowing how much of an effect the DMH has, I think that the most conservative thing to do is to minimize it as much as reasonably possible. And, my point is that it's not just average pool and spa owners that read the posts. There are many people who are able to comprehend the details and want to know. There is an easy way to do anything; the hard part is finding the easy way. I do understand your point. The problem is that there are many people giving people easy answers, and people are getting poor results. The poster was given an easy routine, and ended up with nasty water. If someone is lucky enough to get advice from someone like you who knows exactly what they are doing, then they will get good results. But, how do they know who knows what they're doing, and who doesn't? There are many easy routines, but only a few good ones. You know which ones are good because you understand the science and chemistry behind the routine. I feel that by giving a more thorough, detailed scientific answer people can make better, more informed decisions and get better overall results. I don't like doing things just because someone says that it is the way to do it. I want to know why, and I feel like many others also feel the same way. Of course, people always have the option of skipping the post if they feel that it is more than they want to deal with.
  3. What about my posts is "theoretical"? Is there anything that you disagree with? What do you think might be disastrous? If you want to debate a particular bit of advice, then you need to be specific. What is your advice to the poster? I agree that practical experience and familiarity are important. However, so is understanding the science behind what you're dealing with. Without understanding the science, then you're just guessing and hoping that you get it right. There are plenty of people with practical experience who don't have a clue about what they are doing. BTW, I have plenty of practical experience. I work with pools and spas every day. I also put a lot of time and effort into learning the real science.
  4. I never said that MPS added chlorine to the system. I said that the Onzen was adding chlorine to the spa. The Onzen does not have to be in Boost mode to add chlorine. I agree that MPS can give a false high FC reading on test strips. However, I think that there is more to it than that. I have given the details and the reasons.
  5. The poster notes that they have a background in chemistry and a chemistry degree. Therefore, I think that they would have an interest in the chemistry involved. Here is what I said: My opinion is that until we know for sure the accurate equilibrium equations, we should try to minimize the amount of DMH. It is safer to minimize than not. The above references indicate 200 ppm as the recommended upper limit. I assume that they have reasons and evidence to support their advice. I think that a hot tub that relies heavily on bromine tabs and has high usage could exceed 200 ppm in a 4 month period. Further, if the DMH does have even a fraction of the effect of cyanuric acid, then unless one maintains a proper ratio, the tub will be under sanitized once the DMH reaches any appreciable level. I don't have any problem giving you credit for your extensive contributions, as I noted above. I have read many of your posts, and I have learned a lot from them. Your posts are so numerous and comprehensive that would be difficult to give you the credit you deserve. There really isn't too much that you haven't covered. Anyone giving advice about pools or spas on the boards should probably acknowledge that they routinely use your advice. That being said, I have been doing this for quite a while, so I do know quite a bit about these things. I have plenty of experience, and I do a lot of research. I have known about borates since Proteam first came out. Having a second set of filters is common knowledge for many people in the industry. I do acknowledge that your posts have helped in many areas, but they are only one of many sources.
  6. To calculate the hardness of your water, you can use the pool calculator. It calculates the CSI (Calcite Saturation Index). Be sure to fill in all of the boxes including temperature to get an accurate CSI calculation. A CSI of 0.0 means that the water is fully saturated with calcium carbonate. If you have plaster or grout, then you want a CSI of 0.0 to +0.1. If you don't have plaster or grout, then you want a CSI of -0.3 to -0.1 to avoid scaling. The pool calculator accounts for borate and cyanurate alkalinity, but not phosphate or dimethylhydantoin alkalinity. Phosphate alkalinity can be ignored unless you have added a phosphate based pH buffer. Dimethylhydantoin alkalinity is negligible unless the pH is high and the level of dimethylhydantoin is very high. Dimethylhydantoin has a pKa of 9.19. Here are the correction factors for DMH: pH........% DMH 7.0..........0.251 7.1..........0.315 7.2..........0.396 7.3..........0.497 7.4..........0.623 7.5..........0.78 7.6..........0.98 7.7..........1.22 7.8..........1.53 7.9..........1.91 8.0..........2.37 For example, at a pH of 7.9 and a DMH level of 200 ppm, the DMH will contribute 3.82 ppm to the TA. You should clean your filters according to the instructions here. Most TSP that you will find locally is not real TSP, and does not work as well as real TSP. You can get real TSP here. You should get a second set of filters so that you can allow one to soak while using the other set. I also recommend that you add 50 ppm borates using boric acid, which you can get here.
  7. Waterbear, I know that you worked in retail, and that you have a lot of experience working one-on-one with customers. When you're working one-on-one, you can assess the person's level of experience and tailor the advice to what they are comfortable with. The poster does note that they are familiar with chemistry and have a degree, so I don't think that they will be too overwhelmed. I think that the internet is a unique opportunity to go beyond simple answers and try to give people more detail, and explain the reasons behind the advice. The original poster is not the only person who reads the advice. There are tens or hundreds of people who will read the advice. Each person is at a different experience and skill level. Many of them want to know more than just simple answers. There are many service people who read the advice who can learn something new and improve their ability to give good service. You have certainly written many posts that contain technical details that have educated many service people. Many customers are getting much better service from professionals who have read your posts and applied the knowledge. I try to give more detail for those who are interested, and I also try to make sure that the advice is usable by those who don't want to know the details. Many customers are given easy answers. The problem is that the answers are often wrong. In fact, most people who come on the boards are doing so because they have lost faith in some pool person or company who has been giving them easy answers and they are getting poor results. I would expect them to be a little leery and skeptical about simple advice. If some parts of the advice are too technical for someone, then they can just skip over it. Everyone doesn't have to understand everything all of the time. You know as well as I do that there are a lot of myths and misinformation within the industry. If service is going to improve, then we are going to have to get into the details and the science.
  8. I think that your problem might be associated with high levels of DMH (DimethylHydantoin). DMH is the carrier chemical for bromine tabs and is similar to cyanuric acid. It combines with bromine and helps protect it from degradation by sunlight and ozone. It also slows down the reaction rate of bromine in a similar way to how cyanuric acid slows down the reaction rate of chlorine. The only problem is that we do not know how much of an effect the DMH has on the bromine. I recommend that DMH be limited to 100 ppm. Some references show a 200 mg/l (ppm) limit. Since there is no regular test kit available for DMH, you will need to determine the level by determining the total amount of DBDMH (1,3-dibromo-5,5-dimethylhydantoin) or BCDMH (1-bromo-3-chloro-5,5-dimethylhydantoin), also called organic bromine. For every 10 ppm of bromine supplied by DBDMH, you will get 4 ppm of DMH. Every 1 ounce of DBDMH added to 100 gallons of water will add 83.72 ppm of bromine and 33.56 ppm of DMH. Assuming a 0.70-ounce tab, every DBDMH bromine tab will add 58.60 ppm of bromine and 23.49 ppm of DMH to 100 gallons of water. 1 DBDMH bromine tab added to 400 gallons of water will add 14.65 ppm bromine (measured as Br2) and will add 5.87 ppm of DMH. Every 1 ounce of BCDMH added to 100 gallons of water will add 99.13 ppm of bromine and 39.74 ppm of DMH. (I counted the chlorine as bromine since it will oxidize bromide to bromine quickly.) A 400 gallon tub should limit the total use of bromine tabs to 10 ounces (weight) of BCDMH ((14) 0.70-ounce tabs) or 12 ounces of DBDMH. I recommend that the use of bromine tabs be minimized as much as possible to reduce the effect of the DMH since we do not know how much the effect is. You should use regular, unscented 6 % bleach to provide as much of the sanitizer as possible. You should definitely do the Decontamination procedure. What test kit do you have? How much weight of bromine tabs have you used since the original fill? What do you keep your bromine level at? Note: there is also a newer formulation of bromine BCDMH + DCDMH + DCEMH (1-bromo-3-chloro-5,5-dimethylhydantoin + 1,3-dichloro-5,5-dimethylhydantoin + 1,3-dichloro-5-ethyl-5-methylhydantoin), sometimes referred to as Dantobrom.
  9. On refill, you could use pure sodium chloride instead of the Sea Salt blend. This should eliminate the bromide that is probably in the Sea Salt. However, here is what the manual says: I think that this is nonsense. Pure sodium chloride should work just fine. If it were my spa, I would use regular pure sodium chloride. You will have to decide what you want to use, and if it's worth risking the warranty. You could contact the salt manufacturer to inquire about the bromide content of the salt. You could contact the Onzen manufacturer to inquire about using pure sodium chloride. Another issue that could help explain the increase in FC reading after using the MPS is that your Onzen is making chlorine. Without using the MPS, some of the chlorine will be used up oxidizing contaminants. However, when you use MPS, the MPS will oxidize contaminants and the chlorine produced by the salt system won't get used up. This could account for part of the higher FC reading after using MPS.
  10. You should not leave a tablet feeder in the off position. Once the tabs get wet, they will continue to dissolve and create a dangerous buildup of concentrated chlorine and chlorine gas in the feeder. When you open the feeder valve again, the chlorine will go into your pool anyway. If you open the feeder after it has been closed for a while, you could get gassed with chlorine gas. If the chlorine level is too high, then you need to remove the tabs from the feeder and dispose of them. Allow the feeder to run with the valve open about 75 % for about 10 minutes to clear out the concentrated chlorinebefore turning off the pump and opening the feeder. Once you remove the tabs, allow them to dry and place them in multiple zip loc bags, one inside the other. Do not put them back in the bucket with the dry tabs. Call your local trash service to inquire about proper disposal of the tabs. If your chlorine level is unmanageable, then you are putting too many tabs in the feeder.
  11. I said, "Using hydrogen peroxide to reduce chlorine levels works just fine.". I never recommended it for this spa. Onzen does not use pure sodium chloride. They use a "Sea Salt" blend from the Dead Sea. Sea Salt, especially salt from the Dead Sea, contains bromide. I think that the water probably contains at least a few ppm of bromide, which will become bromine when oxidized by ozone, MPS or chlorine. Any bromine created will affect the FC reading. I recommended that the poster contact the salt maker to inquire about the bromide content of the salt. You are the one confusing the situation by talking about the Genesis salt system, which is not what the poster has. They have the Onzen. You keep going on about what Genesis recommends, which is irrelevant. I agree that the poster should contact the manufacturer to ask about any questions they have. The only thing that I recommended was cyanuric acid. Cyanuric acid won't hurt the salt system. Most salt system manufacturers recommend extra high levels of cyanuric acid. I never said that cyanuric acid should be used with a Genesis system. You are the one who keeps confusing the situation by talking about the Genesis system. The poster does not have a Genesis machine. I don't care what they say. I still think that it's a bad idea. That's my opinion. Just because someone from the manufacturer says something, that doesn't make it right. You are the one who first posted to contradict the advice of others. You are the one who began the debate. I just responded by defending my position. I never "blasted" you or anything you said. I have not been rude to you at all. I have just been discussing the facts and trying to provide as much information as possible.
  12. HHT, yes, I understand that you meant that Sprite was for reducing bromine levels. I did not think that you meant that it was used for shocking. I don't think that it is a good idea to add Sprite to a hot tub. I understand why they don't recommend cyanuric acid. Genesis is a bromine based tub and cyanuric acid won't help. glennmacph does not have a bromine based tub. Well, I am not sure if there is enough bromine to make a difference, or not. Since the tub might be mostly chlorine, then cyanuric acid will probably help, and couldn't hurt. I am not recommending that hydrogen peroxide be used in this tub, or in a bromine based tub. I think that it OK to use in a chlorine based tub, but it should not be something that it needed on a regular basis if the chemistry is carefully maintained. I don't think that I am in any disagreement with Genesis' advice other than to use Sprite, which I think is a bad idea. glennmacph, I recommend that you add 30 ppm cyanuric acid to your tub. You can call the manufacturer of the system if you want to see what they advise. MPS is fine for you to use. You need to determine the amount of MPS that you need to use based on the test results. You should also inquire about the bromide content of the salt. These are just my opinions; you will have to decide what to do.
  13. Genesis uses sodium bromide to generate bromine. Therefore, cyanuric acid would not be helpful for their system. However, 30 ppm should not cause any problems. Hydrogen peroxide would oxidize the bromide to bromine, so it can't be used as a reducing agent, but I don't see any reason it would damage the cell. Post a link to any source that advises adding Sprite to a hot tub. Sprite contains citric acid, which will reduce chlorine or bromine. I don't know how much citric acid Sprite contains, so I don't know how much of an effect it would have. However, I don't think that it is a good thing to use. I think that the sugar would be bad for the water. It would encourage bacteria, and fungus to grow. Using cyanuric acid in a chlorine based pool or hot tub has significant benefits and won't harm the salt system. Using hydrogen peroxide to reduce chlorine levels in a spa with a salt-water chlorine generator should not cause any problems. Obviously, you don't want to make a habit of overproducing chlorine and then neutralizing it, as that is wasteful and causes the cell to work longer than necessary. Some of the oxygen in the hydrogen peroxide probably gets oxidized in the cell to oxygen gas, which reduces the efficiency of the cell, but this shouldn't occur to any great extent as most of the peroxide is oxidized by chlorine. Note: There are some references that indicated that MPS can oxidize chloride to chlorine. I don't think that this happens very much in most pools or hot tubs. However, in this case, where the water is hot and the salt level is at 3,000 ppm, it probably creates some chlorine.
  14. New tubs should be decontaminated. You should do the procedure as shown in this post.
  15. Using hydrogen peroxide to reduce chlorine levels works just fine. However, I suspect that this tub contains enough bromide to make at least part of the measurable FC attributable to bromine. Hydrogen peroxide will oxidize bromide to bromine, and reduce bromine to bromide. Which reaction ends up happening faster depends on the concentrations of reactants. Therefore, hydrogen peroxide might end up reducing the total measured FC, or it might end up increasing it. Note: The dealer indicates that the salt blend does not contain bromine/bromide. However, I think that it probably does because it is not a sodium chloride salt, but a sea salt blend. Some references indicate that the salt comes from the Dead Sea, which is known for its high bromide levels. Use of hydrogen peroxide should not pose a problem with a salt system.
  16. The cell is a rectangular plastic box that contains metal plates. The box (cell) is placed in-line so that water flows over the metal plates. As the chloride in the water contacts the metal plates, it is converted into chlorine. The lifetime of the cell depends on how much total time it is on. The cells are expensive to replace, so it's worthwhile to try to minimize the use of boost mode.
  17. Combined chlorine is also called chloramines. HOCl + NH3 --> NH2Cl + H2O Hypochlorous acid + ammonia --> monochloramine + water To remove the Chloramines, you need to "Shock". Shocking is a process, not a product. It's something you do, not a product that you buy. Chloramines can be oxidized by chlorine, ozone or MPS. 2NH2Cl + HOCl --> N2 + 3H+ + 3Cl- + H2O Monochloramine + hypochlorous acid --> nitrogen gas + hydrogen ions + chloride ions + water 3O3 + NH2Cl --> 2H+ + NO3- + Cl- +3O2 Ozone + monochloramine --> hydrogen ions + nitrate + chloride ions + oxygen gas 3HSO5- + 2NH2CL --> N2 + 3HSO4- + 2HOCl + H2O Peroxymonosulfate + monochloramine --> nitrogen +hydrogen sulfate + hypochlorous acid + water FC can be in the form of hypochlorous acid (HOCl), or hypochlorite (OCl-). How much of each depends on the pH. Hypochlorous acid is the primary oxidizer and disinfectant.
  18. Ok, let's start with the basics. First, you should read the following posts. Nitro's Approach to Water Maintenance Chlorine Demand Dichlor/bleach Method In A Nutshell The dichlor/bleach method is what you want to use. Your salt system will supply most of the chlorine with a little bit of help from bleach as needed. You should turn off your salt system and just use dichlor until you have about 20 to 30 ppm of cyanuric acid. Then you should use your salt system to supply as much of your chlorine as possible without going over. You can make up the difference with bleach or MPS. Chem geek's above guidelines are per person-hour and should be considered a starting point. You will have to adjust the amounts you use based on your test results. You need to get a good test kit. I recommend the Taylor K-2006. It uses FAS-DPD to test for FC and CC. It also includes tests for pH, TA, Calcium and cyanuric acid. You should maintain a CSI of less than -0.2 to help prevent scaling in the chlorine generating cell (assumes that you do not have any plaster or grout). MPS will show up in a combined chlorine test. You might not have had any CC. You can get an MPS interference remover reagent, as chem geek noted above, to measure CC in the presence of MPS. There are several reasons that you tested a high FC after adding the MPS. 1) High levels of MPS can show up on the FC test. 2) MPS oxidized CC to FC. 3) MPS oxidized bromide ions to bromine, which will show up in a FC test. If the salt blend is from the Dead Sea, then it probably contains bromide. Even regular sea salt contains bromide. You probably have at least 6.5 ppm of bromide ions in the water, which will read as 5.8 ppm FC when oxidized by MPS. You could find out who makes the salt and ask them how much bromide it contains. You should avoid MPS for a while and just use bleach to shock as needed until you have a better understanding of your chlorine demand and how much CC you normally get under regular use.
  19. I don't think that it is helpful. I recommend that you don't use it.
  20. 5 ounces is a lot of MPS. Is that how much you normally add? What is the volume of your tub? Are you measuring ounces in volume or by weight? 1 ounce (volume) = 1.3 ounces (weight). The general rule of thumb is about 7 teaspoons of 43 % MPS per person-hour. 7 teaspoons is equal to 1.17 ounces volume or about 1.5 ounces (weight). How did you determine that 5 ounces was needed? What type of chlorine test are you using? Are you using test strips or FAS-DPD? Did you have any CC before adding the MPS? If you have CC, then the MPS could oxidize the nitrogen and convert the CC to FC. Another possibility is if your water contains any bromide ions, then the MPS will oxidize the bromide to bromine, which will register on the FC test. 1 ppm bromide ions will register as .89 ppm FC when oxidized by MPS. Onzen salt blend is made from Dead Sea salt, which has very high concentrations of bromide. Another possibility is that the MPS might be a "Multifunctional Shock", which contains dichlor. MSDS
  21. I think that the "Enhanced Shock" is similar to DuPont Pool Care Multifunctional Shock.(1) (2), which is a blend of dichlor and MPS. This reference indicates that it also contains "sodium tetraborate-pentahydrate as a pH buffer". MSDS for Dupont Multifunctional shock. The D15 contains 15 % dichlor and the D45 contains 45 % dichlor.
  22. You need to test for voltage and current at the element while the heater is supposed to be heating. Don't do this if you are not comfortable working with electricity. Is the contactor closing when the heater is supposed to be heating? http://www.haywardnet.com/pdfs/replace_pdfs/174-175Hay2009.pdf
  23. Mesh covers are not designed to be put on with water tubes. Mesh covers should have anchors in the concrete deck around to pool, and springs on the straps. That way, the cover is held tight above the water as shown in these pictures from loop-loc. http://www.looploc.com/ http://www.meycoproducts.com/PoolCovers.htm
  24. The correction factor depends on the pH. As long as the water is not diluted, then you should apply the following correction factor. pH................correction factor 7.0......................29 ppm 7.1......................33 ppm 7.2......................36 ppm 7.3......................41 ppm 7.4......................45 ppm 7.5......................49 ppm 7.6......................53 ppm 7.7......................56 ppm 7.8......................59 ppm 7.9......................61 ppm 8.0......................63 ppm If the water is diluted, then you would use a smaller correction factor based on the percentage of water dilution. Here is a good source for boric acid. If the tub has any cement, such as from grout or plaster, then the CSI should be kept at about 0.0. If there is no cement, then the CSI should be kept at -0.2 to -0.1 to protect the heater element from scaling. If the heater element gets a coat of scale, it will overheat and rupture. Calcium carbonate gets less soluble as the temperature increases. The phosphate can also create scale, especially as CaHPO4. This scale can create a substrate that encourages the formation of calcium carbonate scale. Therefore, you should be extra careful to avoid a positive CSI. Maintaining a -0.3 to -0.2 is fine as long as there is no grout or plaster.
  • Create New...