CDX looks to be Polyethylene Glycol which might have a reaction with melamine, which is the reagent to test for CYA.
POLYETHER DIOL 25322-68-3
POLYETHER DIOL 25322-68-3
Baqua to Chlorine conversion with cya of 40.
- Thread starter Uckybay
- Start date
- May 23, 2015
- 25,718
- Pool Size
- 16000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
Ok. Hold up. Let’s not jump to conclusions.
The baquacil algaecide is not special. It’s the same algaecide that gets pushed for chlorine pools. It’s just sold as part of the baquacil regimen and up-charged. If it causes problems with the CYA test then you’d see that in chlorine pools as well.
Peroxide is often just stabilized with citric acid. Peroxide is more stable at low pH than at high pH. The opposite is true for chlorine - it’s stabilized with lye so that the pH is above 12.5.
The CDX product contains DBNPA (shorthand for 2,2-dibromo-3-nitrilopropionamide). It’s a biocide that rapidly hydrolyzes into bromine which helps to act as an adjunct sterilizer. It causes problems with conversion because of the added bromine.
The baquacil algaecide is not special. It’s the same algaecide that gets pushed for chlorine pools. It’s just sold as part of the baquacil regimen and up-charged. If it causes problems with the CYA test then you’d see that in chlorine pools as well.
Peroxide is often just stabilized with citric acid. Peroxide is more stable at low pH than at high pH. The opposite is true for chlorine - it’s stabilized with lye so that the pH is above 12.5.
The CDX product contains DBNPA (shorthand for 2,2-dibromo-3-nitrilopropionamide). It’s a biocide that rapidly hydrolyzes into bromine which helps to act as an adjunct sterilizer. It causes problems with conversion because of the added bromine.
PRODUCT NAME: BAQUACIL CDX
CAS OR CHEMICAL NAME CAS # % RANGE
POLYETHER DIOL 25322-68-3
I am not saying that I know that any of the Baquacil products are interfering with the CYA test.
My point is that there might be some interference or maybe a test error since we would not expect there to be CYA in the water.
I would not fully trust the test at this point until the SLAM is complete.
CAS OR CHEMICAL NAME CAS # % RANGE
POLYETHER DIOL 25322-68-3
I am not saying that I know that any of the Baquacil products are interfering with the CYA test.
My point is that there might be some interference or maybe a test error since we would not expect there to be CYA in the water.
I would not fully trust the test at this point until the SLAM is complete.
I'll report back in the morning with the OCLT from tonight. If the chlorine holds, I'm turning the pump off after I test and will test again tomorrow evening before turning the pump back on. That will eliminate any possible role that the filter media could have on the chlorine loss during the daylight hours.
The pool is very clean and the water is very clear. One thing I failed to mention is that my return had pushed my solar cover into a wad on the far end of the pool today. I noticed it as soon as I got home this evening. It wasn't like that when I left this morning and I have no way of knowing how many hours it was like that while I was gone. So not only did I end up getting a lot of direct sunlight in the pool today, any crud that was on top of the cover went directly into the pool. That could have caused the use of the remaining chlorine I had this morning.
Another interesting side note - When I started this process last week, the bleach smell was very strong within the first 30 minutes of bringing it up to slam level of 15. Now, even with a level of 15, the bleach smell isn't nearly as strong, or perhaps I've just become nose-blind to it.
The pool is very clean and the water is very clear. One thing I failed to mention is that my return had pushed my solar cover into a wad on the far end of the pool today. I noticed it as soon as I got home this evening. It wasn't like that when I left this morning and I have no way of knowing how many hours it was like that while I was gone. So not only did I end up getting a lot of direct sunlight in the pool today, any crud that was on top of the cover went directly into the pool. That could have caused the use of the remaining chlorine I had this morning.
Another interesting side note - When I started this process last week, the bleach smell was very strong within the first 30 minutes of bringing it up to slam level of 15. Now, even with a level of 15, the bleach smell isn't nearly as strong, or perhaps I've just become nose-blind to it.
- May 23, 2015
- 25,718
- Pool Size
- 16000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
- Jun 22, 2014
- 52,047
- Pool Size
- 17888
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-45 Plus
That's good. Now it's time to replace the filter media and finish the past few steps of the conversion. Look's like your signature still isn't updated. Can you try to do that today please? It really helps as we progress in your thread to see all your pool and equipment details. See my sig as an example.
Since we do not know the history of the pool, it is possible that someone added CYA or maybe used trichlor or dichlor before converting to Baquagoo.
I will be swapping sand out this evening. 
All FC (15ppm) was lost to the sun today between dawn and 4pm.Pump was off except for the the 30 minutes I ran it before I tested. Pool was well covered with solar cover all day.
I do live on top of a mountain, so maybe I am too close to the sun...
After I get the sand changed this evening, I am just dosing to FC 4 tonight to make sure it holds overnight again.
Any clue why the sun would be so harsh on the chlorine if I am showing cya in the water and the cover is on? Would the pool stay clear if I can only hold chlorine at night?
I guess I should run the full gauntlet of tests once I get the chlorine to 4 tonight? What do you guys think?
I do live on top of a mountain, so maybe I am too close to the sun...
After I get the sand changed this evening, I am just dosing to FC 4 tonight to make sure it holds overnight again.
Any clue why the sun would be so harsh on the chlorine if I am showing cya in the water and the cover is on? Would the pool stay clear if I can only hold chlorine at night?
I guess I should run the full gauntlet of tests once I get the chlorine to 4 tonight? What do you guys think?
- May 23, 2015
- 25,718
- Pool Size
- 16000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
- Jun 22, 2014
- 52,047
- Pool Size
- 17888
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-45 Plus
That means your CYA is very low which makes sense. You still changing the filter media this evening?
Been working on it all evening with a shop vac. Should have it all back together soon. Had to take a break and eat.
No breaks until the work is complete.
We'll let it go this time, but from now on, it's nonstop work, work, work!
But seriously, good job on getting this done.
So now I need to raise the cya gradually to get it to the desired level of 40. I will have to go to Lowes or Walmart to pick something up. Do I need to look specifically in the pool section for stabalizer, or is there something else that isn't specifically targeted for pool owners that I can get in another department, possibly cheaper.
- May 3, 2014
- 62,717
- Pool Size
- 6000
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
It will be in the pool area. Stabilizer aka Conditioner aka CYA. Should be in 4# bags. Normally Clorox or PoolMate. About $20 for 4#.
Thanks. I will get some today.
Since I am showing some level of CYA, I will add this at a rate of 1 pound every 24hrs using the sock in the skimmer method until I reach a cya level of 40-50. Any issues with this plan?
- Jun 1, 2018
- 16,027
- Pool Size
- 26000
- Surface
- Vinyl
- Chlorine
- Salt Water Generator
- SWG Type
- Hayward Aqua Rite (T-15)
You can do 2 # on the first go - that’s 16ppm cya , then retest 24 hours after it’s dissolved.
I guess the other alternative would be to float some trichlor plucks and let the cya build gradually until I get it where I want it.