PaP dude

1) Baking soda is sodium bicarbonate. No matter what wrapper or bucket or pail it is in or how it is advertised, (whether it be arm and hammer, or alkalinity increaser) sodium bicarbonate is sodium bicarbonate, which is baking soda. The pail might say sodium hydrogen carbonate, but that is just a different nomenclature. Just look at the ingredients and make sure that there is no additives. I use arm and hammer myself and have never had a problem, ever. The food store I get it at (Wal-Mart) sells it for 50 cents a pound. 2) Pure BS. Stabilizer, which really is cyanuric acid (CYA), dissolves in water (which some times takes a while) by itself. As Strannik said, dichlor contains CYA in it. For every 10 ppm of FC (free chlorine) added by dichlor, 9 ppm of CYA (stabilizer) is added to the water. The fact that someone tells you to add both would just be adding more CYA than may be needed, which can be a problem. CYA is something you don't want too much of because of its effects on your disinfecting chlorine, (hypochlorous acid or HOCL) that is you would have to increase your FC levels to compensate. (You can read plenty of posts on this forum regarding this issue.) 3) Myth. The addition of any acid chemical, whether it be sodium bisulfate or muriatic acid will both total alkalinity and pH. The acid column or "slugging" effect was dismissed as not true. I think it was in this forum that Chem Geek posted the article about a study that was done regarding the different "methods" of adding acid to a pool, but I can't find it. (If he reads this, maybe he can help me out.) 4) Having optimum circulation in your pool is always a good thing. Sizing the pump and filter up are important. If this is done correctly, you wouldn't necessarily need to run your pool pump 24 hours a day. I usually tell people to run their pump 10 - 12 hours a day in the summer, usually when the sun is beating down on the pool. It is not good for the water to be stagnant when the sun is at its peak in the afternoon. (Assuming your pool is in direct sunlight, or outdoors for that matter.) I live in Florida and this rule of thumb usually works pretty well for my customers and my own pool for that matter. I've never lived in any other kind of climate so I don't know if any thing would change. 5) Metal control products (Jack's magic pink, blue, purple stuff or Natural Chemistry's metal free) are sequestrants or chelators. These chemicals "bind" some metals in solution so they don't precipitate out and stain your surface. Usually clarifiers are some kind of coagulant. This kind of chemical makes solid particles that are suspended in your water (making it appear cloudy: dead algae for example) coagulate or clump up into bigger particles so your filter can filter them out easier. I have never heard of Sea Klear nor do I know its chemical composition so the only thing I can tell you is to try to find the active ingredients. 6) Most pool stores who tell you not to use chlorinating bleach or muriatic acid in a pool with a vinyl liner assumes that the pool owner either neglects or has bad water chemistry. As long as you take care of the water balance (pH, total alkalinity, calcium hardness, CYA etc..) using bleach or acid shouldn't cause you any problems. (So long the pool has water in it) Make sure the water is circulating and poor the chemicals near a jet or walk around the perimeter of the pool while adding. If these chemicals are added carelessly, then damage to the liner can be done. With granular chemicals such as Calcium hypochlorite, it is a good idea to dissolve them before adding. Granular chemicals that are added directly to your pool don't always readily dissolve and can settle to the bottom of your pool. Hope this helps you out some. You should read some other posts on this forum. Lots of good information from some bright minds in pool water chemistry is floating around here.

I am assuming it measures directly the amount of sodium chloride salt (or at least i thought so anyway ) I use the dissolved solid meter shown here. (This link isn't working for some reason but it is the Myron L Pool Meter) I don't really know how it works (if you could tell me, it would be nice) but it usually gives me pretty close results when comparing with test strips that test for sodium chloride. Is my ds meter testing for how much of the chloride ion is in solution or does it some how isolate sodium chloride? I guess that when it comes to pools that use an electrolytic cell to chlorinate, the chloride ion is really what matters. It gets oxidized at the anode to form chlorine gas. The sodium ion is more so a spectator ion since the water molecules are being reduced at the cathode. I would have to agree with you that the salt doesn't matter weather it be sodium chloride, calcium chloride, or even potassium chloride.

I use a dissolved solid meter to test salinity of water. Is this a fairly accurate way? (It is calibrated often with a stock solution)

Thanks.

Well, I usually test my water twice a week. For the most part, everything stays pretty much were I like to keep it. After a big rainstorm I usually have to add a little baking soda to adjust TA, then adjust pH accordingly. I then adjust FC if needed. (Maybe I am just misusing my terminology. Any time I add chlorinating bleach (10.5%) to my pool, I consider this shocking, even if it only small amounts.) Usually, I notice that the FC just slowly drops as the week progresses. It is in direct sunlight all day long and gets minimal use. I usually go in after I do my long distance running. (I do get pretty sweaty and I don't usually rinse off before hand. But this is once or twice a week. ) Based on what I have told you about my pool situation, do you think my FC should drop like it is? I will try to keep my FC about 10% of my CYA like you suggested. I also bought k-2006 test kit that you had recommended so I usually test the FC and CC (as well as everything else) every time I test.

"There are several things to note about the true graph when CYA is present. The first most obvious fact is that hypochlorous acid concentration is significantly reduced, and I’m not talking about 50% reductions or factors of 3 or 5, but rather multiple orders of magnitude – a factor of around 30 in this case. In fact, there are two useful rules of thumb that are reasonably accurate when the CYA level is 5 times or more higher than the FC level (both in their respective ppm) and the pH is near 7.5: RULE #1: The effective chlorine (hypochlorous acid) concentration is reduced by a factor roughly equal to the CYA concentration in ppm. 30 ppm CYA reduces the amount of disinfecting and oxidizing chlorine by roughly a factor of 30. RULE #2: The effective chlorine (hypochlorous acid) concentration is roughly proportional to the FC/CYA ratio. So to maintain the same concentration of disinfecting and oxidizing chlorine when doubling the CYA level, one must double the FC level to keep the FC/CYA ratio roughly constant." Chem Geek, You were helping me out with this information a while back. I am trying to understand basically mathematically how to apply rule 1. First question, when you say the effective chlorine concentration is reduced by a factor roughly equal to the CYA concentration in ppm, are you referring to the ppm of FC or the hypochlorous acid concentration as a percentage? (If that makes any sense ) For example, if my FC is a 5 and my CYA is a 30, the hypochlorous acid concentration would be reduced by a factor of 5/30? This is how I interpret it. Is this wrong? (I have a feeling it might be) Secondly, what is a good FC/CYA ratio? I think I read that keeping your FC 10% of your CYA is good. Lastly, I read that you yourself using 12.5% chlorinating liquid have not had to shock your pool this season. Please tell me how you do this because I am shocking about every 8 days. ( I do live in Florida, and we get tons of rain and my pool is in direct sunlight pretty much all day. Most recent test: CYA = 60 TA = 80, pH = 7.3, CH = 210, FC = 3.5, CC = 0 )

When you calculate your saturation index, are you supposed to use your total alkalinity or your carbonate alkalinity (factoring out roughly a third of your CYA)?

All other factors aside, does one kill better than the other?

I have a question for anyone on this forum. When a pool has an outbreak of algae, is it more effective to just use sodium hypochlorite (yielding hypochlorous acid) or does using a bromide salt (sodium bromide) with an activating agent prove to be more effective? I have some what of a basic idea of how bromine chemistry works, but I really don't know how (chemically) the "bromide bank" gets converted to hypobromous acid, then to bromamines (which aren't bad from what i have read) then back to the bromide bank. I do know that bromine is more effective over a broader range of pH than chlorine (which is why I guess it is popular for spas with warm water and aeration), but is it worth the money for using it in a pool? Any answers, chemical formulas and equations are much appreciated.

Ok, one last question regarding this topic. Where does the aqueous carbon dioxide come from in your pool? Does it come from carbonic acid, or a bicarbonate ion breaking down?

Thank you for clearing this up for me. I had one other question. (sorry, I just want to know all of these things because I am try to pass on this knowledge to co-workers of mine.) I have read many of your post (chem geek) about your explanation of CO2 being out gassed from pools causing a rise in pH with no change in TA. You also mention that pools with SWGs aerate the water because of the hydrogen bubbles it produces at the electrolytic cell. (I understand all of electrochemistry behind that) I guess I am confused on how hydrogen gas bubbles causes carbon dioxide to out gas from the pool. Is this a shift in equilibrium? (from products to reactants) If so, what compounds are actually in equilibrium that causes this?

I think I might have confused myself from reading just about every post on this forum. What I want to know is what exactly does TA measure? I know what role TA plays in water chemistry, I just don't have a clear understanding on what all TA encompasses. Is the amount of sodium bicarbonate dissolved in the water, the amount of carbonates in general, or am I way off? I have read things about carbonate alkalinity, cyanurate alkalinity, and even borates. Can someone clear all of this up for me?

This information is just what I was looking for. I had a feeling that this was going to be complex, but this information is good. Thanks again. Richard C. (Yes, my name is also Richard...not to be confused with chem geek )

I need some help (from chem geek) concerning CYA. I have read many post regarding many things about CYA and have even had Richard show me charts and graphs. (which I found very helpful) What I really need to know is HOW. I got into a conversation with someone about the effects of CYA on the concentration of hypochlorous acid with changing p.H. but I couldn't explain how though. I more interested to know what is happening at a molecular level. Any chemical equations, charts, graphs, anything and everything about CYA would be helpful. Just lay it out. Thank You

Thanks Richard, This information is useful. I really like the pool calculator too! It seems to me that cal-hypo and sodium hypochlorite both have one thing in common...that is they both end up making hypochlorous acid, which does all the work in making your water clean. Knowing this information, I did a mol to mol comparison of the grams of hypochlorite ion available in each product (one pound of 73% calcium hypochlorite vs. 2.5 gallons of 10.5% sodium hypochlorite). It makes sense to me that which ever one can supply the most hypochlorite, would be more effective. (Ignoring the respective cation associated with each along with their effects to the water, Ca2+ and Na+) Click here to see the stoichiometric calculations. **Please note, my work was strictly the calculations...were the additional text may be a bit misleading due to a bias opinion. All in all, the pool calculator seems to be consistent with the results of these calculations comparatively speaking. I just didn't know the respective "strengths" of cal-hypo or sodium hypochlorite in a given volume of water. Some one me that total alkalinity (sodium bicarbonate..baking soda) lowers pH! He had the idea somewhat confused i think (the idea that TA governs the pH by establishing a buffer.....with carbonic acid being a weak acid present in the water and sodium bicarbonate being the salt that contains the conjugate base of that weak acid)