aciam - Nightmare conversion from baquacil to chlorine

[Watermom]

Try that test again. I'm pretty sure those numbers can't be right.

[PoolDoc]

Go purchase a cheap OTO test kit, and see what color you get, please.

I'm concerned about what's happening. I emailed you my phone number.

Ben

[Watermom]

Ben,
Please come back and update this thread and let us know what's up with this pool after you talk with this poster.

[PoolDoc]

These two threads:

http://www.poolforum.com/pf2/showthr...hlorine-Locked
http://www.poolforum.com/pf2/showthr...il-to-chlorine

seem to be both products of an issue I don't remember dealing with before: pools with a LONG history of Baquacil use, before conversion.

I talked with "Aciam" at length last night, and agreed upon the following:

#1 - Test with OTO ; ignore FC / CC differientiation
#2 - Dose to dark yellow (~10ppm); allow it to drop to medium yellow (~2 ppm)
#3 - Continue filtering 24/7
(Aciam's water is clear, but some sort of surface debris is forming continuously and being collected on her skimmer sox)
#4 - Dose with polyquat that the FIRST signs of algae (slippery sides on Aciam's vinyl AG pool)
#5 - If no resolution after a few days, consider drain and refill (AG pools ONLY!)

My **guess** is that there's a huge accumulation of Baqua-goo from the years of Baquacil use, and that -- whatever else Baqua-goo is, chemically speaking -- it is very resistant to chlorine oxidation. The high CC levels are a result of slow (but sure) oxidation by chlorine.

What's weird is that her FAS-DPD readings did NOT match her OTO test results at all. I trust OTO more than DPD, so I made the recommendation above. However, I had to tell her I really have no idea how cleanup will take. I've emailed Chem_Geek to see if he's collected any info on this.

Ben

[PoolDoc]

This is what I posted in the other thread -- but it applies here, too. It's amazing that, having never encountered this here before, we have two simultaneous cases!

Ben

PS. Just found a study of the biodegradation of PHMB. One implication is that, if you let your pool go swampy for a few weeks, bacterial biodegradation of the Baqua-Poop may occur. If you were to try this, and have any of your old filter sand around, you might want to toss some in the pool AFTER the chlorine is gone. Apparently PHMB-eating bacteria accumulate in the filters of PHMB treated swimming pools!

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Hi Reesie;

Just heard from Chem_Geek. He's seen some similar situations on other forums he frequents -- and as best he can tell, the situation is just what I guessed.

You've used Baquacil for years, and have years of "Baqua-poop" or residue from Baquacil in your pool. This stuff is HARDER to break down then Baquacil itself. Apparently, it can take up to 6 weeks to complete the conversion. Richard (Chem_Geek) thinks using sodium percarbonate doses might help, but this is a bit of a guess, too.

Here are links, if you want to try that:
http://www.chemistrystore.com/Sodium...ate_30lbs.html
http://www.soapgoods.com/Sodium-Perc...FB-p-1001.html

The bad news is, I don't think it's safe to swim while your CC levels are so how. If you read aciam's thread, you'll see it hurt her hands to just stick them in the water.

The really bad news is, I can't tell you much of anything definite:
+ Nobody who knows just what "Baqua-poop" (residue from Baquacil use) is is talking or publishing. ICI Americas, who patented the product, probably knows. But they haven't made that info available.
+ So . . . nobody knows what's forming when chlorine breaks Baqua-poop down. Observation (test, smell) indicates that it's some sort of noxious chloramine.
+ And, since nobody knows what it is, nobody is sure how to go about breaking it down faster.
+ Worse, this is such an uncommon event, that nobody has good guidelines to offer you.

Your options:
#1 - Keep chlorinating. It will eventually break down and go away, but it may take weeks more.
#2 - Buy sodium percarbonate and add that, too. (Let us help you with the doses if you do this)
#3 - Add copper sulfate. Copper sulfate (a pool algaecide) breaks down Baquacil; it may break down Baqua-Poop. It probably won't make anything worse. You may be able to get it at Lowes as "Root destroyer" in the plumbing section; you can buy it from the chemistry store link. Again, let me help you with doses if you do this.
#4 - Drain and refill.

I wish I had better news for your.

Ben
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[aciam]

Hi Ben -

thank you for that information. Let me update you on my pool these last 36 hours since we spoke.

On Fri 6/10 at 8am the TC by OTO was >5 as indicated by a brighter yellow than the color on the top most cell. It did not turn orange or brown despite sitting for a while. Out of curiosity(and despite your advice) I tested with my FAS-DPD kit and got a FC of 9 and CC 22.5 ( is the OTO not picking up the weird chloramine that is being created by the baquagoop?)

at 2pm the TC by OTO was again >5 (fc 7.5 and CC 12.5) I added no bleach.

This morning sat 6/11 at 8am the total chlorine by OTO was still >5 but slightly less bright yellow than yesterday I think. (FC 5.5 and CC 5.5)

I have added no bleach since thursday the 9th.

I tested my hypothesis that I had a defective kit/reagents by doing the FAS-DPD on a sample of bleach water that I made up in the kitchen and of course I got a perfectly fine FC reading and a nonexistent CC - so there goes that hypothesis!

A lot of what you are saying makes sense as I review the numbers over the last few days - every time I have added bleach the FC rises a small amount but the CC rises a huge amount - supporting the theory that some weird chemical reaction is occurring to convert the fresh bleach not into free chlorine but some noxious chloramine substance. And it is slow to breakdown as evidence by how slowly my numbers are dropping despite no bleach added in 2 days.

what's weird is that the total chlorine level does not reflect the FAS-DPD total numbers - is it that the OTO can't pick up this new chloramine? Maybe it doesn't matter for swimming????

As you can imagine, none of the options you present seem particularly appealing ( not your fault . Do you know that the sodium percarbonate or copper sulfate will actually work or is that just a guess? I need to mull it all over and talk about it with my husband before deciding our next step.

But let me present this question to you - what is the problem with letting both the CC and FC drop to low levels like around 1-3 - and swimming in the pool over the summer. If I can maintain the FC at an appropriate sanitizing level, and keep the CC low enough so it is not totally offensive, can we just use it while the process of eating up the baquacil just continues over the summer? The pool is crystal clear and blue and so inviting!

My husband asks why, if we can swim in lakes and ponds that have such offensive materials in them, not swim in this pool? Any takers for that one???

I will continue to monitor the pool per your advice and not add bleach now. And then if we decide on the 2 new chemicals you suggested I will post with advice on doses.

Thank you again for all your help. aciam

[waterbear]

The sodium percarbonate will oxidize the biguanide and goo in your pool. However, it will also destroy any chlorine and chloramines present since it creates hydrogen peroxide when dissolved. Therefore, you might need to dose two or three times with the percarbonate for it to be effective if you have high levels of combined chlorine presently. The first applicaton with get used up destroying the chlorine compounds and subsequent applications can then attack the biguanide and residue in the pool.
Normal dosing is 1 lb per 1000 gallon water and since it will cause the pH to rise the addition of 3/4 lb of dry acid for every 1 lb of percarbonate added will keep the pH in line. So for a 10k gallon pool you would need 10 lbs of percarbonate and about 7 lbs of dry acid for each dose. Turn off the pump and broadcast the perscarbonate on the water surface then immediately broadcast the dry acid. The stuff may 'fizz' and cause gunk to float to the surface.
Skim out as much of this as possible then turn on the pump and filter 24/7 for 48 hours. You should have no or little chlorine in the pool at this point and should clean the filter and repeat the process again.
If the water is not clear after another 48 hours of filtration repeat again.

Some people do not add the dry acid initially and let the percarbonate work at the higher pH then lower the pH after the conversion I do not personally know which method is more effective but do know that it does work either way.


At this point what little biguanide remains in the water and filter should be easily oxidized by chlorine if any is left so add chlorine and see how much CC is present or if the water turns colors when you add the chlorine. Once conversion is complete change out your filer medium, be it sand, cartridge, or DE. NO simple backwash here. Break down the filer and clean and soak everything. Repalce the sand, carts or DE completely.

Do not swim in the pool until conversion is compete. The water can be irritating to say the least!

[PoolDoc]

Hi Aciam;

Waterbear has described the percarbonate method above, but your situation is somewhat unique. I've never used that method, and am a bit skeptical. (Waterbear, you say percarbonate releases peroxide. But if so, how does that help? Baquacil Shok is very strong peroxide.)

Chem_Geek is confident that percarbonate will work FASTER in a regular conversion of PHMB, but your PHMB is already gone; what's left is 'Baqua-poop' or degraded Baquacil. Chem_Geek is NOT sure that percarbonate will work better (or even at all) against Baqua-poop.

Do I know whether copper or copper + silver or copper + silver + monopersulfate will work? No, not at all. I'm pretty sure that chlorine will work eventually, but I can't give you any time frame. There have been references to similar situations, but I haven't been able to find them, and to such conversions taking 6 weeks, but I don't know!

But, I completely agree with Waterbear on swimming: this is NOT like swimming in a dirty lake. Ordinary chloramines can be very irritating to skin and the genitals. I don't know what is in your pool, but as you already noted, it hurt your hand.

Sorry I have so little info. I spent 3 hours on research this afternoon, and only found out how much is NOT known.

Ben

[waterbear]

Baquacil Shok is very strong peroxide.

Stabilized with citric acid and with a low pH. The percarbonate will be at normal pool pH if the acid is added or quite alkaline if it is not. While I have no data as to which is more effective I suspect the pH plays and important role here and that NOT adding the acid until after the conversion is the more effective route since stabilized 27% peroxide does not appear to destroy biguanide to any great extent, nor does MPS, which is also acidic. I have also seen patent data that indicates that sodium persulfate, which is also normally acidic, does not degrade biguanide to any great extent but at high pH it does.