Trouble clearing pool

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Can you run another FAS-DPD test this morning and see what you get?

If your test results are correct, you're going to have to just keep doing what you're doing. Raise FC to 10 and hold it there. CCs will form, but they will be oxidized by the sun and more FC. Eventually everything will come down to where it's supposed it, it will just take awhile.
 
If your CYA was high when you closed your pool and now it's much lower and is not explained by water dilution and you let the FC get to zero over the winter and you've now got a huge chlorine demand that has created a lot of CC, then this sounds to me like bacteria converted your CYA into ammonia. You just need to keep adding chlorine until it holds consistently and gets rid of the CC. If you want to estimate how much chlorine that will take, you can do a bucket test and scale accordingly. Just note that it will take chlorine several hours to get rid of the CC when there is CYA present (with no CYA it takes around 10 minutes or so).

You can read about how I got through this in the thread It Can Happen to Anyone - Zero Chlorine, CYA-->Ammonia and in particular this post that summarizes what it took in my situation to get through it.

You should not use a DPD test, but really need to use the FAS-DPD test to make any sense of what is going on. As was noted, just maintain a high FC level which given your 30 ppm CYA a level of 10 ppm or so (12 ppm would be normal SLAM level at 30 ppm CYA so that's fine as well). This is NOT going to damage your liner. It's only equivalent to an FC that is 0.6 ppm FC with no CYA.
 
Thanks. I still show no FC after putting in 12 gallons of 12.5 bleach since this morning. Do I keep adding until I see FC? Under normal conditions this should have put roughly 60ppm in the pool. Is this damaging to my liner. By the way I did the ammonia test and it was above 6ppm (the highest it can read).
 
I just reread and saw that your CYA is now less than 20 ppm so an FC target of 10 ppm is reasonable for this situation. You indicated in an earlier post in this thread that your CYA may have been 150 or so. If indeed bacteria converted 130 ppm CYA (probably not because some probably got diluted from rain overflow), then that would need roughly 3 times that amount of FC so around 390 ppm FC cumulatively added to get rid of it. That's worst case, but possible. Yet another reason why having a high CYA level is risky -- if bacteria convert it to ammonia, you have a HUGE chlorine demand in front of you.

As I noted, you can use a bucket test if you want to estimate how much chlorine you will actually need. You may decide that a partial drain/refill might be more economical for you. For a bucket test, 1/4 teaspoon of 6% bleach in 2 gallons is 10 ppm FC; 1/4 teaspoon of 8.25% bleach in 2 gallons is around 14 ppm FC.
 
midwestpool said:
Thanks. I still show no FC after putting in 12 gallons of 12.5 bleach since this morning. Do I keep adding until I see FC? Under normal conditions this should have put roughly 60ppm in the pool. Is this damaging to my liner. By the way I did the ammonia test and it was above 6ppm (the highest it can read).
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Hey - I agree with Chem Geek - you may want to do a partial drain... question first - did you get the 6ppm of Ammonia after adding the 12 gallons or before? If it was before - repeat the ammonia test. If it was after, and you want to do the partial drain, refill, recirculate, redo ammonia test. I've found it really is about 10:1 ratio of chlorine to ammonia to get rid of the ammonia. Getting the ammonia down through water replacement means less chlorine to use, assuming your water isn't expensive? If you're getting a good deal on the chlorine might be a wash...

You can add the chlorine every 15-30 minutes, I wouldn't wait longer. Calculate and add enough to reach your target - add it all per the recommended method (in front of return, leave pump running) test the FC after 30 minutes. No or low FC means repeat the that process until you get a FC reading. I've never seen liner fade from using this process and I've treated ammonia multiple times. Oxidized 4ppm ammonia in a 35,000 gal pool in about 4 hours, approx 16 gal. The harder you hit it the faster the process will go and the less chlorine you'll need in the long run to complete the SLAM process.
 
OK getting pretty frustrated now. Now the ammonia is still above 6ppm(who know how high). I retested the FC and it was 7. CC was over 25 before I stopped using all my drops. Am I getting a false reading on the FC test? The reason I ask is that I have also been using the strips to test. I show no FC on the strips. I did the bucket test with the strips and once I added 3/4 oz of chlorine to 1 gallon of pool water the strips finally registered a FC. My CYA appears to now be at 20 at least. I have had a sock with stabalizer in the skimmer. Where to now?
 
If the ammonia is still above 6 I would do a partial drain and refill and begin the process again. You do not have a FC reading - that is interference from the extremely high CC level. I know exactly what you are talking about and it's almost a brownish pink when doing the FC test. Disregard the strips they will only confuse you.

Did you get refills for the FAS-DPD test - you will need them.

Where did you purchase the ammonia test? Mine goes up to 8. You can use a 2:1 distilled water dilution to read twice as high as your chart goes.
 
Thanks. Are you saying I have no FC based on the ammonia level? Just trying to learn. I'll forget the strips but is even the FAS_DPD test inaccurate because of the CC at this point? Also, any idea how much water I can safely drain out of my pool at one time?
 

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This morning I can barely see the floor drains in the deep end so it still slowly starting to clear. My readings are:

PH 7.1
FC 28
CC 7
TA 350
CYA 25-30

Can I be sure my FC reading (fas-dpd) is correct with such high CC? My CC is down from yesterday though. Also, I have been brushing the pool everyday. This morning I could see little dark spots on the floor that spread into the water once the brush goes by. I assume this is algae. Is this because so much of the chlorine is tied up getting rid of the CC?
 
In your situation, the FC is working on algae, ammonia, bacteria and other organics that may be in the water. I'm pretty sure the FAS-DPD test is accurate even at high FC and/or CC levels up to 50ppm. That's why it is recommended.

With your FC as high as it is and your CC getting closer to zero I would say you're almost out of the woods!

Can someone please confirm that I have this right and correct me if I am wrong? When FC encounters the ammonia that was created from CYA over the winter, it's immediately converted into combined chloramines. In a normal situation sunlight breaks down small amounts of CC throughout the day, but with CC's so high only more FC will break them down fast enough to be of any practical help?
 
Yesterday I continued with the SLAM process unti I finally ran out off bleach at 9pm. I was adding 2 gallons of 12.5% every hour and retesting. The CC continued to rise during this process and FC was erratic. Sometimes it was double digits others it was single. Is this normal? This morning I have not added anything yet and my measurement are FC 26 and CC 10. Not sure where to go at this point?
 
The symptoms you describe are classic for a pool that has ammonia in it. The solution is more and more chlorine until you burn off the ammonia.....then your FC will hold. (The ammonia will burn off very quickly so keep adding more FC until you get the CC's down to .5 ppm or zero.)

I am only repeating what I have read on this forum so others may have more info but I am pretty comfortable with what I have said.
 
This morning I finally have 0 CC and 15ppm of FC. I think I finally made it! Can someone explain to me why my strips still show no free chlorine even though the fas-dpd test measures 15? It's not because its bleached out because when I add some drops of bleach to a small sample the strips then show free chlorine. Very weird. The pool store said they have never encountered this.
 
+1

Sometimes they'll give high readings, sometimes low, other times they completely fail and give no reading. Think of them as a bad dream, just try to forget about them.

Smykowski said:
Strips are not worth the time or effort of figuring them out. If you have a drop based test kit, you'll save yourself a lot of stress it you just throw them away.
Click to expand...
 
Not sure what is going on but now I have 4ppm combined chlorine. Still showing 15 free chlorine. The water is still cloudy and I can see small dark spot on the floor that appear to be algae. Any thoughts? Is it possible that the powder turning pink in the sample is a false positive because of combined chlorine?


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