FC testing post-Jack's #2 Copper

[tmarcoux]

I completed a Jack's #2 Copper treatment in late October when the water temperature was in the 70's. Shortly after it was completed, we had a cold snap and it dropped the pool temperature quickly below 65 degrees, and it's not 52 degrees. The instructions from Jack's was that post-treatement, to expect FC readings to be zero, and to measure chlorine levels via TC (FC+CC). I also understand that the colder water temperatures may increase the time to continue this practice until the FC readings come back.

It's been 2 months now and I still get a FC reading of zero, and a CC reading of 3-4ppm. My CYA was also low and I had a couple of pucks remaining so I have a couple floaters in there to add CL and CYA - so there is a source of CL.

Given all this, I am good by continuing to measure CL using TC until the water warms up?

Here are my current readings:

FC=0
CC=4
TA=60
CYA=60
CH=??? (reads 400ppm, but that's higher than before Jack's treatment - where it was 300ppm)
Borates = 40
Temperature = 52 degrees
Salt = 2600 (but SWG currently off for the winter)

I also add Jack's purple to 10ppm to keep copper in check (it comes from my water source)

Thanks

 

[easttn]

I dont know what is in Jack's #2 Copper or what the instructions say to do, but if you put chlorine (FC) in your pool it is there instantly (giving it time to mix before testing of course). The FC is either being eat up by Jack's #2 Copper ingredients, Jack's purple, algae, or other organics. If you havent had FC in two months the colder water may have saved you from seeing algae grow.

Is your pool still open or closed?

 

[tmarcoux]

According to their website and instructions:

TIP: This treatment can produce false free chlorine readings for 3-4 weeks; use the total chlorine reading during this time

My understanding is that it is a false reading, not necessarily consuming the FC; that said, it's been more than the 3-4 weeks.

The pool is open-ish. I live in Austin Texas so I don't close the pool; however, it has a spa attached so that does get used. Only the brave (or those standing too close with a balance issue) go swimming.

 

[easttn]

Oh ok. I remember seeing that somewhere now. If that is the case then I would use the TC reading and add enough bleach to raise the TC to slam level. That should help to get things straightened back out.

Slam Level FC is 24ppm.
http://www.troublefreepool.com/content/128-chlorine-cya-chart-slam-shock

24ppm of FC - 3ppm of TC (which you already measured) = 21ppm of FC to add (507 fl oz of 8.25% bleach)
http://www.troublefreepool.com/calc.html

It may take several times and several days. Make sure your pool pump is running if its not so it will circulate.

 

[chem geek]

See the thread Rebalancing after Jack's Magic #2. As noted in that thread, raising the chlorine to SLAM levels will speed up the process especially since it's quite slow at colder temperatures, but you could just live with it since eventually it will recover especially when the water warms back up. Up to you, of course.

 

[tmarcoux]

Got it! Thanks for the link to the post.

One more question before I begin the SLAM process. Do high CL levels breakdown the sequesterant (The Purple Stuff) and re-release the metal into the water? If so, should I perform a filter change prior to SLAM?

My copper source is our fill water, but that source has been off for the winter. I keep a 10ppm of Jack's Purple Stuff.

Off to the store!

 

[chem geek]

Yes, the chlorine may break down the sequestrant so if the copper is supposed to get caught in the filter you'd want to clean that out before doing the SLAM.

 

[tmarcoux]

So I need a sanity check.

I've been SLAMing now for about a week, adding bleach at least twice a day to get my FC=24. After a week, I am now getting:

FC=20
CC=30

I'm about to add bleach to get back to 24. I seem to be feeding the CC monster! That said, I have been adding less over time to get to SLAM level. I keep telling myself to be patient, but need reassurance. Will keeping FC=24 eventually eradicate CC in amounts over 24ppm?

Also, what is the optimal time to allow between reading/adding CL?

 

[duraleigh]

Something is wrong, I think, How are you testing (what kit) ?

 

[tmarcoux]

TF100

It's taking 40 drops for FC test and 60 for the CC to clear. SOP. I've tested it twice with similar results. I'm running out of reagents!

The water is way too cold for any algae growth, so should I leave it alone for a week and see what happens? This Jacks#2 stuff is my source of CC.

 

[JasonLion]

I would leave it alone until the water warms up. The reaction that breaks down the Jack's #2 chemical runs very slowly at cold temperatures.

 

[tmarcoux]

Since there is a spa attached, at what point is it safe again to use the spa? Or am I closed for the season???

 

[JasonLion]

If nothing goes wrong, you just need FC+CC to be in the normal range for FC and you should be fine. That assumes that there isn't any actual CC, only Jack's #2 making FC appear as CC, which is going to be true nearly all of the time.

 

[tmarcoux]

Just so I'm not guessing - that would be 3-7ppm for FC? I'm assuming 20 is too high

 

[chem geek]

For your 60 ppm CYA level and with an SWG it's a minimum 3 ppm FC but yes you could go higher if you wanted to. You can swim up to shock level which is 24 ppm but there's no reason for you to keep it that high. A 3-7 ppm target range is fine.

As for the spa, since it's attached just use the same numbers as the pool. At a higher FC level you will notice more chlorine/chloramine smell during your soaks so you'll probably want to be on the lower end of FC when you start your soak. If you don't mix with the pool water right after your soak, then you'll need to add chlorine to the spa after your soak. Every person-hour of soaking in a hot (104ºF) spa with no ozonator requires around 3-1/2 fluid ounces of 8.25% bleach to oxidize the bather waste.