high cc

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Well, there you go. The fact that you were maintaining some FC in a few of your tests and appeared to still have some CYA made us question whether it was really ammonia causing the high CC.

Now you just have to keep adding bleach up to shock level ever 30+ minutes until the FC holds and the CC drop.
 
I think i was misreading the test my looking for pink too closely. I used the amount of bleach from the pool match page to raise to shock level and after 40 minutes of scrubbing the pool my reading was only 2ppm FC. I added 4 more jugs, we'll see what happens in half an hour. I just set the pump to recirculate thinking maybe i will get more flow in the pool if i bypass the filter; the water is clear. Good idea?
 
Note that the ammonia test does not distinguish between ammonia and monochloramine. Nevertheless, even if there is monochloramine there, it pretty much had to originally come from ammonia before you added the chlorine (at least for the relatively large amounts you are seeing).

So basically if you opened with ammonia you could have read zero in the CC test though if you had tested for ammonia you would have found ammonia. After adding chlorine, it combines with ammonia to produce monochloramine and that shows up as CC and still shows up in the ammonia test (because the ammonia test technically adds Dichlor to the sample to create monochloramine and what you are measuring is creation of a dye from monochloramine reacting with salicylate and getting oxidized further). As you add more chlorine you may find that the CC keeps rising as more monochloramine is formed quickly until you've close to exhausted the ammonia. At that point, additional chlorine will oxidize the monochloramine and both the CC and "ammonia" (really monochloramine) will drop.

The units of measurement for CC are 5 times higher than for ammonia so what looks to be around 2 ppm ammonia (as ppm N) would produce around 10 ppm CC. That will take not quite 10 ppm FC to get rid of so you're almost there (though that image might be 4 ppm ammonia in which case it would take more like 20 ppm FC). At any rate, you just keep adding chlorine until the CC goes away and the FC starts to hold without loss overnight.
 
With a moderate amount of CYA in the water it takes around 4 hours to get ammonia and CC down to levels below what your test kits will measure. With no CYA in the water it's much faster at around 10 minutes. You're definitely on the right track.
 

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Hey Chem Geek, can the high ammonia levels (or CC levels) bleed into the FC portion of the test? Wondering if that could explain some of the odd readings at the beginning of this adventure.
 
I will take credit for the inaccurate readings. It was the first day I had the dpd/fas test. Now my CC pink is the light pink my fc was when I started indicating I had no fc when I reported I did. Current level FC=14.5 CC=1. Check again in the morning. If my CC goes to zero and I pass the ammonia test am I done with the SLAM and can allow FC to drift back to normal?
 
High CC levels can bleed into the FC test especially if one waits longer.

As for when you're done with the SLAM, it's not only when CC is <= 0.5 ppm (in practice it could be <= 0.2 ppm) but also when the overnight FC loss is < 1 ppm.

If the "jugs" or bleach are 121 fluid ounces, then 21 jugs of 8.25% in 30,000 gallons is 60 ppm FC. That's pretty high, but you could have had other chemicals besides ammonia such as partially broken down CYA that would not show up as ammonia and might not show up as CC but would create a large chlorine demand.
 
So the CC is OK but the FC loss was 2.5 ppm which is a little high. There is some test error when the FC is higher but I'd go another day and night and test overnight again to be sure. I'll bet the loss is lower the next night. Since you weren't fighting algae and the FC is mostly holding, you could lower the FC if you wanted to and just note that your chlorine demand will still be a little higher than normal for a while, but it will take longer to get that fully back to normal if you end the SLAM early.
 
Thanks Chem Geek. I added a little more bleach to raise the chl by 2ppm per the pool math chart to hold the shock level while I am at work today. After I am done shocking and the CF levels are back to normal is it OK to cover the pool again? I had a solar cover on it all last summer and didn't have any problems; though I have a pretty high swimmer load so the cover was removed almost ever day for at least a few hours. It is never sunny in Cleveland so I try to minimize heater use with the cover. I am not that technical, but is the monochloramine created when chlorine at non-shock levels reacts with ammonia meaning the bleach I initially added was creating more problems that it was solving? What creates the ammonia so I can try to avoid it in the future?
 
Since you have to get rid of the ammonia by adding chlorine to it anyway, you didn't create any new problems. By adding chlorine first you just made it a little harder to know definitively that you started out with ammonia, but pretty much you won't get high CC as you did that goes away fairly easily with chlorine if you didn't start out with ammonia. In your case, it also seems like there was something else as well, such as partially degraded CYA.

As for your cover, it should not be a problem. You just need to maintain an appropriate FC/CYA level and you should be fine.

What likely happened to your pool was that after you closed the FC went to zero at some point and then bacteria grew and converted the CYA into ammonia and partially degraded CYA by-products (see this thread for technical details). Such bacteria are anaerobic so prefer little oxygen so a pool that has the pump off might stagnate and have some aerobic bacteria use up the oxygen allowing the other bacteria to munch away at the CYA. To avoid this, you'd need to either maintain the pool over the winter with chlorine (not possible if you have to close the pool due to freezing conditions) or close it with some algaecide in it such as Polyquat 60 (see this post). Also, close the pool as late as possible so that the water is 50ºF or colder and open as early as possible before the water gets above 50ºF.
 

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