Bromine Chemistry Question

[FormerBromineUser]

Thanks, guys, so, SO much. I was really hoping to have a sanitized pool by my party on Sunday but I'm sol on that.... I can still see the main drain clearly but the intervening water is getting grayer and grayer. Less than 48 hours to go and counting!

Based on Ben's suggestion early on, I have added nine 3.78 quart bottles of Clorox (8.25%) at night. In the morning, my strips are off the chart (>20 dark green) for chlorine but by afternoon, zero. That's why I don't understand this: "What Chem Geek was suggesting and I was seconding was that you might have extremely high chlorine level. So high that the chlorine / bromine tests are getting bleached out." Why would I get readings after adding beach? I am so confused. Also, after I add chlorine, I can smell it. When I can't, the strips read zero. I think the sunlight is stealing everything I pour in. In the past when I accidentally let my tabs get low, I super-chlorinated and the pool bounced back so that I only used bromine tabs and oxy-sheen oxidizer; no straight chlorine. The bromine tabs seemed to survive the sun but then again, the auto-cover worked and I closed it when the pool was not in use.

You all know so much more than I do. To me, the following is incomprehensible: " If the CYA wasn't greater than 100 then there wasn't enough to become the chlorine demand you're seeing through conversion to ammonia." My mind keeps saying that I don't have ammonia so what the heck are they talking about. Btw, I checked my local HomeDepot, Walmart, Target.... Not one had OTO kits, just refills. It's just as well as now I will just get the Taylor K2006.

Ben, I wanted to let you know that years ago I realized that my son's doctor was wrong. I had only mentioned the issue in order to accept responsibility for the bromine vs. chlorine decision when we built our pool back in '05. My pool guys are not perfect but the bromine call was mine, not theirs... Also, I read how you receive a commission from amazon by folks linking through you. I have already bookmarked your link as my way onto amazon's site. I only spend about a thou at amazon each year but I hope my part helps. I appreciate all you have done for me and all the many, many people on poolforum. What a great service you all provide.

[chem geek]

So the fact that your strips were off the chart after adding the chlorine but then it was all gone by the afternoon may indicate something in the water with a huge chlorine demand still present. Next time you do this, add the chlorine at night after the sun is down, measure it within 30 minutes (with the pump running), keep the pump running overnight and measure the chlorine/bromine in the morning. That will eliminate the possibility of it going away from sunlight due to a lack of CYA (though the measurements showed some CYA, but I don't trust test strips, especially not for CYA).

As for previously having a high CYA level before this problem started, I think that very likely if you were using

Super Soluble that I used last year as: "Sodium dichloro-s-triainetrione dihydrate"

since that is Dichlor where for every 10 ppm FC that you added, it also increased CYA by 9 ppm. So unless you had a lot of water dilution, your CYA may indeed have been very high. And as I noted, you roughly triple the CYA level that dropped to get the FC chlorine demand that could result if bacteria converted the CYA into ammonia. I'm not sure if I trust the pool store with their ammonia test, though as Ben says it doesn't really matter what the source of the demand is, eventually you can get through it with enough chlorine. I'm just concerned that it could still be an awful lot left to go. What's the volume of your pool? Perhaps it would have been easier and cheaper to replace most of the water instead.

You could do a bucket test to get an idea for the chlorine demand left in your pool -- presumably that is what the pool store was doing with their "chlorine demand test", but perhaps they weren't doing it correctly. In 2 gallons of pool water, every 1/4 teaspoon of 6% bleach will be 10 ppm FC so you can see how much of this you have to add before you register chlorine/bromine that doesn't go away.

[PoolDoc]

A couple of quick comments:

1. Get the refill kit; use the OTO in a small bottle or tube. The colors you'll be seeing aren't on the test block anyhow. When you order the K2006, order an OTO kit, too. They are useful, and cheaper for a quick test, than the K2006.

2. Keep your pH high; that will minimize the smell. Also, do test the water with the local OTO, BEFORE anyone swims. Notice whether there's much color change between the color 5 seconds after adding and mixing, and 1 minute later. If so, do NOT swim. The change indicates high chloramine levels that will be very irritating. Especially, do not let your son in the pool.

3. Tell us how long you've used bromine -- has it been since 2005? If so, you're probably going to need to plan a water change (NOT: drain -- you can't drain a vinyl pool) to remove the accumulated DMH.). But I need to check -- for all I know, it's possible that DMH can be biodegraded to ammonia in a manner analogous to what happens to cyanuric acid. If so, it may be gone. But, I don't know how to test for that.

4. You may want to look at this, about contact dermatitis due to DMH: http://www.postermedic.com/parcdesal...imas105237.pdf

[FormerBromineUser]

Thanks again, guys. Here are some comments/answers in the order they appear above:

CHEM_GEEK: I add chlorine at late dusk (so I can still see). My pump runs 24/7 from Spring open to Fall close. I will check 30 minutes after adding my next dose, but in the past, when I measure in the morning, my test strips are >20. The stronger the dose of chlorine, the longer it takes to get back to zero but it eventually does within a few days. I don't know what you mean by "eliminate the possibility it going away from sunlight due to lack of CYA" but those are my results.

I checked with the pool store and they DID use a lot of dichlor last year, more than I thought. I used only one bottle of Super Soluble but THEY added (at their expense) a bunch of Super Soluble last year. Because it was a freebie, there is no record of the quantity but I remember it was at least 50 lbs. and could have been as much as 70. Since last year there has been no addition of products containing dichlor.

I added an avator of my pool as it is today. Not that it helps as the picture is so small. I took the picture from my second floor and from there I can still see the main drain. My pool is around 30,000 gallons. The Bioguard rep suggested replacing 2 feet of water to get my CYA down to under 25 and then retest the chlorine demand which is when I began this thread in the first place. I never did the draining, but I did add about an inch and a half of water since then.

I will try the bucket test after the party tomorrow. Then I will know how much chlorine to add. If this assumption is incorrect, please let me know.

POOLDOC: Last night I took a pool sample in to the pool store to test pH. (I am not a good judge of that color spectrum). They said it was at 7.8. I added between 1/5-1/4 gallon of muriatic acid.

I ran an OTO test today. Light, light yellow. The color did NOT change at all after one minute.

I have been using bromine since it was built in 2005.

I ran my own ammonia test today. It was very yellow and so no ammonia.

Thanks for the link about contact dermatitis. It was very interesting and explains why my nephew gets a rash in my pool! He now takes a shower after each swim which takes care of the problem.

[FormerBromineUser]

Hello, there. I am not sure that anyone of you guys are still following this thread, but I wanted you to know that the pool stayed clear up until my big party! It is now grey, no chlorine by afternoon, but I am at least putting bleach in every night, kind of like throwing money in the pool but maybe I will keep something at bay. We have decided to keep the pool at this level for as long as we can instead of trying to meet our chlorine demand which according to the bucket test you suggested is still astronomical. We will use it as long as we can, checking for PH and CC and stuff so it is "safe" to swim.

We have also made a huge decision to get a new liner. We have some serious "snakes" from when we had a drainage issue and water got under our liner. Our plan is to do this in the April next year. I am thinking about going to the BBB method BUT, I cannot find a start to finish explanation of how to go about doing it. There are bits and pieces of information here and there, but I can't find a complete step-by-step "how-to" guide. I have read and reread the BBB Method page and I don't feel confident that I really know what I am supposed to do.

I also have the following fears:
1.) The only directions I have read for starting out with ALL NEW water requires hourly maintenance until the chemicals are in balance. I can't do that as I work a heavy schedule until the end of May. Is there any alternative?
2.) We do travel during the summer. I have seen that some people use tablets for a long weekend. Still scary. If we go away for a week, I guess I would have to find someone to take care of it that knows BBB and I have no idea how to find anyone!
3.) We also are sometimes spontaneous about night activities and don't get home until late once in a while. It seems like BBB has to be done EVERY night after sundown. I'm just not sure I can in reality keep that up.
4.) Coming from 9 years of bromine use, I am still having difficulty understanding the relationships between CC, PH, CYA, TA, etc. I really have read and read posts about this but it is still foreign to me. I have not really every had to worry about more than bromine/chlorine levels and PH.

Considering all these fears, what do you guys think about me going to BBB?

Thanks. If I don't hear from any of you, I will try to re-post this somewhere else. Thanks in advance!

Reminder: 30,000 gallon in ground vinyl liner pool

[chem geek]

If you use a mostly opaque pool cover, then the loss of chlorine from sunlight is virtually eliminated and you can add chlorine a lot less frequently. That's what we have, a mostly opaque electric safety cover, so I only add chlorine twice a week. Even those with bubble-type covers usually don't have to add chlorine every day, but rather every other day. Nevertheless, adding chlorine every day (or two) is just a quick and easy task. If you want automation, then you can look at getting a saltwater chlorine generator or using The Liquidator or getting a peristaltic pump. I think the bigger issue for you in terms of maintenance will be the weight of chlorinating liquid or bleach you have to carry to maintain your larger 30,000 gallon pool. If it uses 2 ppm FC per day, then that's 3.4 gallons of 12.5% chlorinating liquid or around 31 pounds per week. With 8.25% bleach, it's around 43 pounds per week.

As for CH, pH and TA, you don't have to worry about these so much in a vinyl liner pool -- regardless of whether you use bromine or chlorine. It's only a problem if you water is hard (CH and/or TA very high) as that can cause scaling. With a vinyl liner, you don't need to worry about the CH if it's low. Once you get your TA to a typically lower level (usually around 80 ppm) where the pH is relatively stable, then you don't need to worry about it.

The only real "extra" chemistry with chlorine is the CYA level. The CC is hardly ever an issue and is almost always low -- mine is nearly always <= 0.2 ppm, the lowest measurable using a 25 ml water sample.

As for startup with a fresh water fill, I don't think it takes hourly maintenance. That is probably referring to new plaster where in the beginning the water chemistry changes quickly as the plaster cures, but for a fresh water fill in an existing pool you can balance everything in one shot and not need to stick around.

[FormerBromineUser]

Nervous, nervous nervous! New liner, dark auto-cover, and water going in today! ...and I will no longer be a "BromineUser". Worked VERY hard last fall to learn BBT method (with my bromine pool) and ended up after tons of chlorine, having a beautiful pool. Wanted to say hi as you will be hearing from me soon! I am so nervous!

[PoolDoc]

Good luck!

If you haven't already, make sure to order a K2006 test kit or whatever refills you need (link to info page in my blue signature box). Especially when you are new to BBB pool care, accurate testing is essential. Test strips are never very accurate, but the accuracy of strip testing for CYA is abysmally poor.