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quantumchromodynamics

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  1. Shocking and filtration should resolve the sulfur issue. Note: Some pools use an alternative sanitizer called Baquacil. If the previous owners used Baquacil, then you cannot shock with chlorine or MPS (unless you decide to do a full conversion). You should ask the previous owners if they ever used Baquacil. If the previous owners are not available, you could have the water tested for Baquacil at the local pool store. Also, what chemicals did the previous owners leave for you? Did they leave any test kits?
  2. I would try to keep the CSI between -0.3 and -0.1. Your numbers are pretty good right now. I think that if you started to use a pH of 7.8 or 7.9, your pH would be more stable. The right TA is going to depend on where you want to keep the pH. The lower you want to keep the pH, the lower you need to keep the TA to maintain a stable pH. A pH of 7.8 to 7.9 should be stable with a TA of 60 ppm. If you wanted to use a pH of 7.5 or 7.6, then you will probably need to use a TA of 50 ppm. Once you get the pH and TA stable, then you want to adjust the Calcium to where you get in the -0.3 to -0.1 range. The offgassing of carbon dioxide causes the pH to rise. The rate of offgassing depends on factors such as temperature, aeration and the concentration of carbon dioxide. This chart shows the concentration of carbon dioxide in ppm at various pHs and TAs (TA as carbonate alkalinity). .......................................................TA 100...TA 80....TA 60....TA 50 pH..........X........%CO2....%HCO3.... CO2........CO2.......CO2......CO2 7.5......-1.15........6.61..........93.39......6.23.........4.98........3.74.......3.12 7.6......-1.25........5.32..........94.68......4.94.........3.95........2.96.......2.47 7.7......-1.35........4.28..........95.72......3.93.........3.14........2.36.......1.97 7.8......-1.45........3.43..........96.57......3.12.........2.50........1.87.......1.56 7.9......-1.55........2.74..........97.26......2.48.........1.98........1.49........1.24 There is the same amount of carbon dioxide dissolved in the water at the following: pH = 7.5 and TA = 50 pH = 7.7 and TA = 80 pH = 7.8 and TA = 100 or pH = 7.6 and TA = 50 pH = 7.8 and TA = 80 pH = 7.9 and TA = 100 Increasing the pH by only 0.3 will allow you to maintain a TA of about 50 ppm higher with about the same amount of stability. Every 0.1 increase in the pH corresponds to an increase in TA of about 17 ppm for the same stability. I think that you will begin to see good stability at a carbon dioxide concentration of about 2 ppm or less, such as pH =7.7 and TA =50, or PH = 7.9 and TA =80. However, this is still above the Henry's law concentration of aqueous Carbon dioxide, which is 1.2 x 10^-5 mole per liter at 25 C (77 F), which equals 0.528 ppm. Chem geek has a chart here that shows a similar thing.
  3. I think that you mean CH 100 and TA 80? You don't want a higher TA; a higher TA will cause more pH rise. To reduce pH rise, you can use a higher pH and a lower TA. Using a pH of 7.6 to 7.9 and a TA of 40 to 70 should give good stability. Right now, you could increase your borates to 50 for more pH buffering. You could also target a slightly higher pH of 7.8 to reduce pH rise. If you increase your borates to 50 ppm, then you could target a pH of 7.9.
  4. The chunks could be calcium carbonate. What do the chunks look like? What do they feel like? Try putting them in some vinegar to see if they will dissolve. What are all of your chemical readings? Free chlorine Combined chlorine pH Total alkalinity Calcium Cyanuric acid Temperature Note: Swirl Away contains surfactants, trisodium phosphate, tetrasodium iminodisuccinate and sodium bicarbonate.
  5. Any sulfur in the water that would cause a "sulfur smell" would be in the form of H2S (hydrogen sulfide), which is in equilibrium with the hydrogen sulfide anion HS- (pKa H2S = 7.00). Any hydrogen sulfide should have been oxidized to sulfur or sulfate if the pool has been treated with chlorine. HS- + OCl- --> S + Cl- + OH- HS- + 4 OCl- --> SO42- + 4Cl- Any elemental sulfur should be filtered out. The sulfur would be best filtered by a DE filter, although you might need to use an activated carbon filter to remove final suspended sulfur. Sulfates shouldn't cause any smell. Shock to about 10 ppm using liquid chlorine (sodium hypochlorite) and keep it there until all of the sulfide has been oxidized. Hydrogen peroxide can also be used to oxidize the sulfide to sulfur or sulfate if the chlorine does not work. Hydrogen peroxide is a chlorine reducer so you would have to use enough to reduce all of the chlorine and then add about 3 ppm hydrogen peroxide for every 1 ppm sulfide. pH needs to be raised to about 8.2 for this to be most effective. A properly designed, installed and operated ozone system can give very good water quality. However, a well designed system is expensive for the initial setup. Reference Use of MPS (aka non-chlorine shock) to shock might help oxidize sulfides to either sulfur or to sulfate. Have you had the water tested for hydrogen sulfide? What are all of your other chemical readings? Free chlorine Combined chlorine pH Total alkalinity Calcium Cyanuric acid Temperature
  6. Ozone primarily reduces chlorine to chloride. There are two different reactions of ozone with hypochlorite ions. O3 + OCl- --> 2O2 + Cl- ozone + hypochlorite --> oxygen + chloride ion 2 O3 + OCl- --> 2O2 + ClO3- ozone + hypochlorite --> oxygen + chlorate The first reaction accounts for 77 % of the reactions and the second reaction accounts for 23 % of the reactions.
  7. http://www.americanfloormats.com/locker-room-pool-mats/ http://www.americanfloormats.com/turtle-tile-shower-matting/ http://www.americanfloormats.com/duragrid-deck-matting/
  8. I don't think that there is a clearly superior product. There are many factors that go into the strength and durability of the structural shell. 1) The experience and expertise of the builder. 2) The thickness of the shell. 3) The strength ratings of the concrete. 4) The diameter and spacing of the rebar. 5) The preparation of the ground. As for mixing application types, you don't want to do that. The shell should be shot in one continuous process to achieve a monolithic structure with no cold joints.
  9. Ask the diver if there was a hydrostat, and if there was, what did it look like?
  10. I answered the OP's question. I also provided additional information because there are people who want that type of information.
  11. As you can see in the picture, the valve is a pretty simple device. There is a main body and a cover plate. The cover plate slides up and down on a center pole. There is an O-ring at the top of the main body, which you can see in the picture. There is a spring on the center pole that helps keep the plate down. The valve is threaded into the main drain. When there is more water pressure under the valve than above it, then the valve will open to allow water to go from under the pool into the pool. Usually, if the valve gets pulled up by suction, it will fall back down and reseal. However, sometimes grit will cause it to not fully seal and there will be a leak. Sometimes it can reseal on its own. The valve can leak at the threads and it can leak if the O-ring becomes deteriorated. The diver probably should have replaced it while he was down there, especially if it is the original one. I usually try to keep minimum suction on main drains. Most of the time, I leave them turned off. The main drain cover needs to be replaced with a new cover and properly secured before anyone uses the pool. A loose, broken or missing cover is a serious safety hazard. The new cover needs to be compliant with the new safety standards.
  12. For heavily used spas, an ozonator will reduce oxidizer demand. For lightly used spas, an ozonator will tend to increase the amount of chlorine that needs to be added. This is because ozone oxidizes bather wastes, but it can also react with chlorine and convert it into chloride or chlorate. The silver won't have much of an effect either way on the amount of oxidizer demand.
  13. I think that as long as the minimum temperature is above 40 degrees F for 4 days before plastering, the day of plastering, and until the pool is full, then temperature shouldn't be a problem. During periods of daily rain, the local water table can get higher than normal, which can increase the risk of floating, or water weeping through the gunite while plastering. However, the water table can be controlled to prevent the possibility of the pool floating and to prevent the possibility of water weeping into the area between the plaster and the underlying concrete. You don't want to plaster on a windy or rainy day. Here are a few references you can review if you want further, more detailed information. The last reference link might not work, is primarily for commercial pools, and is really too much information, so you should probably skip that one. Reference 1 Reference 2 Reference 3 Reference 4 Reference 5
  14. I would suspect the hydrostatic relief valve. If the main drain gets covered, there can be enough suction to cause the hydrostat to open and it can get stuck due to debris. The valve can then reclose on its own. This time of year, there are more leaves, which might be covering the main drain. How much suction do you have on the main drain? Do you ever run the vacuum head directly over the main drain? That can also cause it to lift up and leak. Hydrostat in the open position. Do you know what your local water table is? If you dug a hole in your backyard, how deep could you go before hitting water? Another thing to consider is that if the water is heated and uncovered, then it will lose substantially more water due to evaporation when the air temperature is lower.
  15. My most recent post is my answer in my own words. I did not get the information from any other source. I only require three things that should be fairly easy to get. A swimming pool is a luxury. If someone does not have access to basic supplies, then perhaps a swimming pool should not be on the top of their priority list. If the person does not have even basic transportation, then why are they buying a pool? What happens when they need food or need to get to a doctor? If he can get a swimming pool, then he can get the things I suggest from the same place. I need certain tools to do my job properly. There is no need to compromise on that. I give exact amounts of chemicals to add based on the test results. That's as easy as it's going to get.
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