Bright Orange Chlorine Test Results - Damaging?

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Bright Orange Chlorine Test Results - Damaging?

Postby georgia » Tue 30 Oct, 2007 17:55

I have a 20K gallon, in-ground, salt-water-generator, gunite finish, 7 years old pool 17x33 feet.

Last Saturday, 4 days ago, I added 4 pounds of Algae Spot Kill (by BioGuard). Active chemical was Trichloro-s-triazinetrione (99.%) to kill Black Algae spors.

SWG has been off since then and pump running about 8 hrs day. We've been mostly cloudy too. And no rain.

On the good side, the algae is gone. However, when testing for Chlorine with my 5-drops OTO test kit, it returns a bright orange result.

I understand sunshine will eventually knock down the chlorine level as will draining and replacing the water.

But in the meantime, am I hurting my SWG cell and/or pump by running water thru the system this high in chlorine? Or am I damaging my pool gunite finish?

Thanks for any and all help!
georgia
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Postby chem geek » Tue 30 Oct, 2007 19:46

4 pounds of Trichlor in 20,000 gallons will raise the FC by 22 ppm and will also add 13 ppm Cyanuric Acid (CYA) to the water. Assuming you had some CYA to begin with, you won't be damaging any equipment with this high chlorine level. It's around the level one would do for shock, again dependent on the CYA level.

The FC will drop over time -- especially if there is any sunlight.

More importantly, you should get a good test kit, such as the Taylor K-2006, and see what your CYA level is. You should not be getting algae if you maintain a minimum FC level of 7.5% of the CYA level (a target FC of 11.5% of the CYA level is better).

Richard
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Postby georgia » Wed 31 Oct, 2007 15:54

Richard - chem geek:

Thanks for the reply, info and suggestion.

I did get the water tested today at the store. Amazingly it showed 2.9 ppm Free Chlorine and 1.2 ppm Total Chlorine (for a Combined Chlorine of -1.7).

However, prior to going to the store I tested it at home with the 5-drop test kit. And it was that super-dark yellow, almost orange again.

As such, I am ASSUMING the store's reading are correct (or reasonably close) and my test kit drops are simply reacting to the active ingredient in the 4 pounds of Spot Kill algae killer. Is that a reasonable assumption or am I totally off track?

I know nothing about "Total Chlorine" ranges so I've got to check into that. Store clerk said it was nothing to worry about.

Re the Cyanuric Acid, it tested at 37 ppm. The low end of the range (30 to 150 ppm), but still in specs.

I was low on the Alkalinity at 57 ppm (range being 80 - 150 ppm). So I've added 5 pounds of Sodium Bicarbonate. Store clerk says that will not be enough, however, I'm just going slow as no body is swimming any longer. We're just golfing and enjoying the occassional adult beverages this time of year.

PH came in a 7.6 and Hardness at 187 ppm, both in range. Salt was high (my fault) at 4,000 ppm. Drained off and put in about 600 gallons.

I'll check on that Taylor K-2006 kit as well. Mine owes me nothing after all these years.

Thanks again!
georgia
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Postby chem geek » Wed 31 Oct, 2007 18:13

If the algaecide was BioGuard Spot Kill, then this is just Trichlor in powder form, so essentially the same as Trichlor pucks/tabs that just dissolves faster. It adds to both chlorine and CYA.

I don't know why you get such seemingly different results than your pool store, but getting the K-2006 test kit should help as it is accurate and can measure up to 50 ppm chlorine (both FC and CC).
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Postby georgia » Fri 02 Nov, 2007 06:53

Good morning from Georgia.

Just as a follow-up, I had the water retested (yesterday, Thursday). FC and TC readings from them essential the same (2.6 and 1.8 ppm respectively) as the day before.

Cleaned out the filter cartridge and cell last night as the sun finally appeared. I had not done so since adding the Triclor powder.

I am, however, still getting the very dark yellow from the chlorine test drops here with my home test kit. You did not comment on my "assumption" that perhaps that was happening as a reaction to that 4 pounds of Triclor from last Saturday. Could that be the cause or am I off track?

I did check out that K-2006 test kit. Wow, so much better than mine. They offered a 3/4 oz and 2 oz reagent size bottle. Do you think this business of replacing your reagents yearly is actually necessary or is it simply a marketing scheme?

In my case, the test kit and 1 oz reagent bottles sit up on the porch, in shade, year round. And truthfully, I don't replace them until they are empty.

Thanks in advance for the info and assist.
georgia
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Postby chem geek » Fri 02 Nov, 2007 13:04

Yes, the 4 pounds of Trichlor adding 22 ppm FC would make a Free Chlorine test register > 5 ppm so would be very dark (yellow/orange for OTO test; DPD test would bleach out). So yes, that was the cause. The chlorine level will continue to drop over time -- especially if the water is exposed to the UV rays of sunlight.

The part about replacing reagents is valid, but every year is overkill for most of the reagents. Some will last a very long time -- the acid and base demand reagents are like that. Next are the indicator dyes. The ones that last the least are the FAS/DPD titration drops since they are sensitive to light -- that is, the R-0871. If you want a good bargain and a better combination of reagent sizes, most of which provide 36% more volume so more tests than the K-2006, then check out the TF100 here. It will also test the CYA level down to 20 ppm. The pH test is different than the K-2006 -- it shows a wider range with less granularity (it shows 6.8, 7.2, 7.5, 7.8, 8.2 vs. the K-2006 that shows 7.0, 7.2, 7.4, 7.6, 7.8, 8.0). I started with the K-2006, but now have a TF100. The TF100 uses Taylor reagents so it's really just a more intelligently packaged Taylor K-2006 with more logical sizes for the reagents. I show the contents of the TF100 in this thread.

You can prevent getting algae in the future by maintaining an absolute minimum Free Chorine (FC) level that is at least 7.5% of the Cyanuric Acid (CYA) level. A better target is an FC level that is 11.5% of the CYA level (roughly 10% of the CYA level is fine). So it's important to not only use stabilized chlorine (Trichlor or Dichlor) and instead to use unstabilized chlorine (unscented bleach or chlorinating liquid or Cal-Hypo) though with Cal-Hypo you need to watch the Calcium Hardness (CH) levels.

For every 1 ppm FC added by Trichlor, it also adds 0.6 ppm to CYA. For every 1 ppm FC added by Dichlor, it also adds 0.9 ppm to CYA. For every 1 ppm FC added by Cal-Hypo, it also adds 0.7 ppm to CH. The problem is that whereas the FC will drop over time (i.e. get used up), the CYA and CH will not as these only decline via splash-out or dilution (CYA can slowly degrade in other ways, usually over a winter when a pool is "let go" without chlorine).

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Bright Orange Chlorine Test Results - Damaging?

Postby georgia » Sun 04 Nov, 2007 15:44

Thanks for the information and suggestions. I've learned a lot.

I'm going to go with the TF100 kit you recommended.

For any readers following this thread with a similar condition, this is now the eighth day since adding that 4 pounds of Trichlor.

I just tested the chlorine with my 5-drop kit. The really dark yellow - almost orange color is gone. It test still is dark, but improving. We've had 3 days of sun which I'm sure has helped. I would say 2 to 3 more days and I should be back in the normal range.

Again thanks, and best regards from Georgia.
georgia
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Postby chem geek » Sun 04 Nov, 2007 22:59

georgia wrote:Just as a follow-up, I had the water retested (yesterday, Thursday). FC and TC readings from them essential the same (2.6 and 1.8 ppm respectively) as the day before.

I can't explain why others are measuring far lower chlorine readings than your OTO test (the one that is yellow/orange) is showing. Unless your sample wasn't in a sealed container or was exposed to sunlight, I don't know why they didn't measure high chlorine levels.
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Bright Orange Chlorine Test Results - Damaging?

Postby vangie » Fri 22 May, 2009 20:00

Is this dangerous to your health
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Bright Orange Chlorine Test Results - Damaging?

Postby chem geek » Fri 22 May, 2009 20:24

Is what dangerous to your health? A bright orange in an OTO chlorine test? It means the Free Chlorine (FC) level is very high. As to whether this is dangerous, that depends on the Cyanuric Acid (CYA) level. Odds are that there is CYA in the pool if it is an outdoor pool and then the high FC level won't be nearly as bad. In fact, the active chlorine level may not be any more than found in indoor pools with no CYA. I wouldn't drink the water, but being in it won't hurt you -- but one should just wait until the FC drops to at least below 10 ppm.
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