Chlorine lock?

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cholmes28

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Jun 9, 2014
213
Marietta, GA
I am new to the TFP methods. I am trying to get my CYA to around 50-60 so I can start the SLAM. I have been draining and filling for past week, and testing using my Taylor K-2006. I wasn't sure if I was reading the test correctly because it was still showing like 75, so I ran up to the pool store and they said it was 58. All other tests are within the recommended ranges. So last night, I decided to add 64oz Clorox Germicidal Bleach which is 8.3%, to see if it would raise chlorine level at all. I just tested (18 hrs after bleach add), and after putting in the 2 scoops of the dpd powder, the water did not even turn pink, which I guess indicates there is no chlorine?

So my first question is, if the water doesn't turn pink, does that mean there is no chlorine, or no free chlorine? I am confused since I cannot do part 2 of the test, if there is no pink to turn clear.

Second, the pool calculator suggested 121 oz of 8.3% bleach to raise 27k gal pool from 0 to 3, and I only put in about half, so I assumed I would at least raise it to like 1.5, but it is still 0. I just tested CYA again, and according to my readings, I am still at about 75. Is that high enough to allow all that bleach to get "eaten up" by the sun in one day?

My other tests are:

Calcium Hard: 100 (vinyl liner)
Alkalinity: 70 (I put about 7 lbs baking soda in 4 hrs before bleach, but haven't tested since)
pH: 7.4
 
Not turning pink means you have no FC ... it was consumed by something ... and you really did not add enough to do anything anyway.

Did you do the CC portion of the test? You would add the 5 drops of R-0003 and see if that turns pink.

High CYA would protect more of the FC from the sun.

You need to decide if you are going to try to lower the CYA some more first, or if you are just going to follow the ShockLevelAndMAINTAIN Process now.

You might should review this again: ABCs of Water Chemistry
 
The term chlorine lock is misleading, so the term used here is "over-stabilization". You could get to the correct FC level by going to around 8 PPM FC, but you also mentioned you're planning to do a SLAM. The SLAM will take considerably less bleach if you lower your CYA before the SLAM. A partial drain/refill will get this done.

Adding your pool details to your signature will be very helpful and this is described in "Read before you post" (there's a link in my signature below)
 
I did not realize I could continue with the CC test, if the water did not turn pink in step 1. I just redid both tests, and the CC = .2 (1 drop to change to colorless). Also, when I add the 2 scoops of dpd, they don't disolve, they clump together in 2 little balls, and won't disolve by swirling, unless I cap and shake vigorously. I just read the ABC's again and I guess I was off a bit on the role of CYA. Essentially, if the CYA is high, then I need add more chlorine to maintain the desired level. Last summer, my CYA was around 50, and I would add about 5 lbs of dichlor weekly, and never had any algea. This summer I was doing the same, and the day after addeing it, chlorine was gone. That is when I found out my CYA was 100. Been draining and refilling, and now it is down to 60 or 75 depending on Leslie's reading or mine. I just want to get to the point where I can pour in xx oz of Clorox per week, and keep the water safe and algea free.
 
Thanks for explaining. That makes sense. Just a caution that one addition per week is unlikely to work well. You might get away with as few as three, but most threads here that I've read suggest every other day is workable. The key is to maintain your FC level so that it never goes below minimum for your CYA level.

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p.s. the 10 ml FC test is fine for everything we do. I'm surprised by the clumping. All I can think of is to keep the powder and your scoop as dry as possible.
 
After reading about the SLAM yet another time, it would seem that is is really desigigned for those who have a bunch of algea, or not clear water or some big issue. In my case, my water is crystal clear, but about 3 days after I add my weekly 5 lbs of dichlor, I start to see some yellow (really yellow, not mustard yellow) staining appear where the walls meet the pool bottom. By the time the week is up, when I brush, that yellow has migrated to other places on the bottom. WHen I brush, it takes a few passes to get rid of it. I assumed it was some type of algea. The main purpose in jumping on the TFPC bandwagon, is that I want to rid the need to buy chemicals labeled for pools, and their inflated prices. Perhaps I don't really need to SLAM, I just need to make certain the CYA is low enough to be able to add my bleach at whatever the recommended dose and frequency is to maintain proper balance.
 
cholmes28 said:
After reading about the SLAM yet another time, it would seem that is is really desigigned for those who have a bunch of algea, or not clear water or some big issue. In my case, my water is crystal clear, but about 3 days after I add my weekly 5 lbs of dichlor, I start to see some yellow (really yellow, not mustard yellow) staining appear where the walls meet the pool bottom. By the time the week is up, when I brush, that yellow has migrated to other places on the bottom. WHen I brush, it takes a few passes to get rid of it. I assumed it was some type of algea. The main purpose in jumping on the TFPC bandwagon, is that I want to rid the need to buy chemicals labeled for pools, and their inflated prices. Perhaps I don't really need to SLAM, I just need to make certain the CYA is low enough to be able to add my bleach at whatever the recommended dose and frequency is to maintain proper balance.
Click to expand...


In your case, there is only one way to know for sure if you need to SLAM. And that is to perform a proper OCLT. You can search if you don't know what that is
 
Trust your CYA results. You are at 80 as we round up when you are midway. You need to raise your FC up to 9ppm just to hit your target. If you are going to slam, it would be 31ppm.

Are you planning on doing more draining to lower your CYA further?

Please don't use any more dichlor as it is raising your CYA even higher.
 
My experience is that once you rid the pool of algae, and then keep chlorine above the minimum for your CYA, consumption of FC goes down a lot. The criteria for needing a SLAM includes visible signs of algae. You can tell if it's algae, by brushing, and you see that it's still there. The stain later disappears from adequate FC. So it's clearly algae, and will keep coming back until it's annihilated from that spot. The SLAM annihilates the existing algae, then all you're killing is whatever blows in and is carried in.

Always keep one thing in mind. The presence of algae is used as an indicator for FC levels that are too low, and when FC levels are too low, you're risking too slow a kill of bacteria. Killing bacteria keeps your pool safe for people.
 
So if there is zero FC in the pool now, then obviously I need to get it up to 3 before I do the OCLT. But how do I get it there, if everytime I add Dichlor, or more recently 8.3% bleach, the next day, the FC is back at zero? As I mentioned in my first post, I added 64 oz of 8.3% Clorox last night at 9 PM, and by today at 3 PM, the FC was zero. I guess my CYA is still too high? According to Leslie's it is 58, according to my test, it is 75. Do I need to drain/fill more water before I can do the OCLT?
 

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MarianParoo said:
Trust your CYA results. You are at 80 as we round up when you are midway. You need to raise your FC up to 9ppm just to hit your target. If you are going to slam, it would be 31ppm.

Are you planning on doing more draining to lower your CYA further?

Please don't use any more dichlor as it is raising your CYA even higher.
Click to expand...

WHen you say I need to raise my FC to 9ppm to hit my target, what does that mean? Are you saying that I need to put 9 in the target field of the calculator, which says I need to add 353oz of bleach? Sorry, just a little green with all this right now, so thanks if you can explain. Also, I am done with dichlor, or anything else that is marketed for pool use. I was thinking about draining more water to get the CYA down more before I do an OCLT.
 
I would hold on the OCLT until you resolve what I consider a more important issue.
but about 3 days after I add my weekly 5 lbs of dichlor,
Click to expand...
I shuddered just a bit when I read that. PoolMath tells me that that dosage increase FC by 12, (That's OK) CYA by 11 (that's each week!!) and drops pH rather significantly? Are you awqare 0of that?

What is the purpose of the dichlor?
 
Did not realize that it was increasing CYA. I have been using the dichlor as a weekly shock treatment for years. The exact product I was using was Pool Time Shock Plus from Home Depot, which is 58% Sodium dichloro-s-triazinetrione. One thing I did differently this year is that I usually close the pool for the winter, which means I drain water below jets, then fill when I open. This year, I did not drain, and used a floater with jumbo tabs all winter. I was probably increasing CYA all flippin winter and since i did not have to add water this time, the levels remained.
 
Yep, 353 ounces 8.25% is a good number to get to 9 ppm FC. And abandoning dichlor as a source for chlorine is a great decision. (along with all the other over-priced stuff!)

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No problem asking lots of questions. You got this, and it will all sink in really well as you work through it.

Finding your best source of chlorinating liquid will also help you keep your costs down. There's good threads here for that, such as 2016 bleach prices

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Lots of people have fallen into the "over-stabilization" trap, which is why TFP has so many members and is such an active forum!!! TFP really helps pool owners get off the pool $tore treadmill with all the great info here. And you end up with a safe, sparkly pool as a result.
 
Is super chlorinating to 9ppm for the OCLT, going to render the pool non-swimmable for a period of time? Also, if it is the sunlight that eats the chlorine, then it would seem that the OCLT is really only testing to see if it is algea that is consuming the chlorine, correct? If I don't lose any FC overnight, but I am still losing it during the day, then what do we do next?
 

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