First results. First steps.

BS_LM

Active member
Aug 11, 2019
30
Twin Cities, MN
Pool cover was closed last night due to threatening weather. Opened autocover in the morning and will continue to keep it open. Tested this morning then added 7 gallons of liquid chlorine post test. Results are as follows:

FC: 3.5
CC: 3.5
pH: 6.8

Made another trip to Menards to purchase more liquid chlorine. Just completed testing water at 3:15 and added another 7 1/2 gallons of liquid chlorine post test. Results are as follows:

FC: 6.5
CC: 5.0
pH: 6.8

Retested FC at 3:45 and the result is 14.0. FC SLAM level goal is 33. PoolMath is suggesting another 5.3 gallons.

We have not yet reached the FC SLAM level goal, thus we have continued to re-add liquid chlorine a couple times per day as time permits. I have enough to do a 3rd SLAM today, then I'll have to make another trip to Menards.

-Lori
 

aeh0603

Well-known member
Apr 6, 2016
237
San Diego, CA
The more often you can test your FC and dose to your SLAM level, the faster your SLAM will go. At this point, your FC is not yet holding, it looks like in your 30 minute test you dosed to 33FC and 30 minutes later tested at 14FC. This is a huge loss in such a short amount of time and this combined with your high CC levels is usually indicative of ammonia in the water.

How long ago did you test your CYA level? Can you do me a favor and check your CYA level again to see if it is still what you think it is? There is a bacteria that eats CYA and converts it to ammonia, so I just want to do a sanity check to make sure that is not what you are dealing with. Typically this is found more with swampy pools upon opening for the season, but based on your test results so far I just want to verify.

Are you sure no one has added an ammonia based algaecide recently?
 

BS_LM

Active member
Aug 11, 2019
30
Twin Cities, MN
@aeh0603 A repeat CYA level is 90. I think this is more accurate as Lori and I were concentrating on the black dot the last(and first) time we did the study 3 days ago. Tonight, just a quick glance led us to the 90. If I understand the ammonia issue correctly, if we had the bug that chews CYA and spews ammonia, our CYA levels should have dropped. I understand that we might still have an ammonia issue from another problem, like an algecide, and Lori added algecide about one month ago, but we don’t know if it was ammonia based or not.

Most recent results one 30 minutes after the most recent addition of about 5.7 gallons of liquid chlorine:

pH-7.2
FC-12.0
CC-9.5
CYA-90 (and no, we have added no dichlor or trichlor-rather the difference from our first is likely interpretation error)

And now we are off to buy out the store from the remaining chlorine... Don’t think we will get to the pet store tonight for ammonia testing. Maybe tomorrow.
-Bryan
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
22,397
Laughlin, NV
There must be some chemical reason for the CC being tested. Or a testing error.

Check everything. CC results you are showing are very confusing with minimal organics and no ammonia.
 
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BS_LM

Active member
Aug 11, 2019
30
Twin Cities, MN
Back from Menards, where we left some boxes of chlorine behind, as there is only so much room in the back of a small SUV. We just repeated a FC level(about 1 1/2 hour after last 5+ gallons of chlorine was added) and the FC level is 13.5.

@mknauss Likely we will not be able to do complete testing now as it is getting dark and I must return to work. I will plug the FC in pool math with CYA at 90 and add additional chlorine with goal of getting FC to near or at SLAM level and that will be it tonight. Full test again in am. I am very confident in the recent FC, CC, CYA, and pH tests, if reagents aren’t bad in brand new TF-100.
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
22,397
Laughlin, NV
I understand. But the CC is defying reality.

Why are you not draining/exchanging some of this water? Nearly impossible to successfully follow the SLAM process at a CYA of 90.
 

BS_LM

Active member
Aug 11, 2019
30
Twin Cities, MN
@mknauss I made the decision to SLAM instead of drain/exchange 3 days ago when I thought the CYA was at 80(upper limits of acceptable for SWG pool) and felt that SLAMing would be more time efficient, if more costly, than the d/e. Who would have thought that the CC would misbehave in ways that no one here seems to understand(I don’t, but CC only came on my radar last week when I came to this site). So we are where we are now and have a pool party in 4 days. The water looks great, and I don’t believe that the CC levels will negatively impact swimmers, so I will hold off on drain/exchange until opportunity allows.

In the meantime, we do appreciate any thoughts and ideas about how to proceed. I just added about another 5.5 gallons of 12.5% chlorine, turning the deep end into a lovely, persistent, green that is slowly dissipating now. Lori will repeat full tests in am.

-Bryan
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
22,397
Laughlin, NV
If your CC is truly the level you are testing, the water will be very uncomfortable for swimmers. Eye irritation, etc. Also, the water should stink very strongly of chlorine.

If it does not, then the CC is not real. It is due to some additive used recently that is creating a false reading.
 

BS_LM

Active member
Aug 11, 2019
30
Twin Cities, MN
A little research suggests that a principal additive that will lead to false CC levels is monopersulfate. To my knowledge, we have not added this. Does anyone know if it is commonplace for pool stores to use this when opening pools. We have hired our pool’s builder and operator of our local pool store to open and close the pool each season. I have no idea what they have used in the process.

What other additives falsely elevate CC?
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
22,397
Laughlin, NV
MPS or non chlorine shock is the most likely culprit to give false CC readings. But if done at opening, it should be long gone.

Be sure your test vials are clean. Use alcohol to clean them. That can give false CC readings, but not as high as you are reading.
 

kimkats

Mod Squad
LifeTime Supporter
Jul 10, 2012
41,019
Tallahassee, FL
You are holding some FC so I would not bother with the ammonia test as if you had ammonia you would not hold any FC.

Do you mind walking us through how you do the CC test? Just to be on the safe side.

How does your pool area smell? Have you been in the water lately? How does it feel on your skin?

Marty is one of the best. He will be able to help you out during the day.
 

BS_LM

Active member
Aug 11, 2019
30
Twin Cities, MN
Completed full testing this morning, but did not have alcohol on hand to clean test vials. I rinsed them thoroughly with water prior to testing.

@kimkats Here are my steps in doing the CC test: Put 10 ml water in Chlorine Only cylinder, added heaping scoop of R-0870 powder, swirled to mix and it turned pink, added R-0871 one drop at a time until clear, multiplied by 0.5 to get FC. Then added 5 drops of R-0003 and it turned pink. Finally added R-0871 one drop at a time until the solution was clear, multiplied by 0.5 to get CC reading.

The water is sparkling clear, no smells, and feels fine on my skin.

Here are the complete set of testing results this morning:

FC: 4.0
CC: 2.5
pH: 7.1
CH: 500+ (solution turned lavender at 20 drops and it was purple at 38 drops...but it was never blue)
TA: 260
CYA: 75

Knowing that we have a big pool party this coming Sunday, should I continue to add liquid chlorine to SLAM level goal today (which we have not yet achieved our goal) with the plan to drain the pool post party or just maintain the FC at an appropriate swimming level the next few days until post party and then drain?

I sincerely appreciate your thoughts/ideas on how to proceed.
-Lori
 
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kimkats

Mod Squad
LifeTime Supporter
Jul 10, 2012
41,019
Tallahassee, FL
I would keep on with the SLAM to be on the safe side. You do NOT want to take any chances of it doing anything "funny" before your party! We will work on the CC when you are done.

That is THE way to test so I know you are getting solid numbers. Thanks for doing that!!!
 

BS_LM

Active member
Aug 11, 2019
30
Twin Cities, MN
Purchased alcohol to clean test vials. Early afternoon, I added 8 gallons of liquid chlorine based on late morning testing (results posted in above thread) Re-tested one hour later:

FC: 13.0
CC: 5.0

Then added another 6 gallons of liquid chlorine and tested an hour later:

FC: 14.0
CC: 8.0

Early evening, we hit the pool with another 6 gallons of liquid chlorine and an hour later completed 2 FC and CC tests. This time, we used a 12 mm syringe to accurately measure 5 cc of tap water & 5 cc of pool water. The first test was with the products in our new kit (that's what we've used in all the previous tests) and the second test was with duplicate products that we purchased for when we used up our kit's products.

Test 1: (from the kit)
FC: 10
CC: 6

Test 2: (from the additional agents purchased separately)
FC: 8
CC: 6

Water is clear and has no odor.
-Lori
 

BS_LM

Active member
Aug 11, 2019
30
Twin Cities, MN
@frogabog Simply trying to conserve reagents, especially as we anticipate, “any time now,” a bump to FC 30 and the need for 60+ drops to discover this. So a 1:1 dilution with tap water(presumed 0 FC, though we did not test to confirm) and no division by 2 after adding drops, should give us a good estimate of the FC and CC. Used the syringe to get a very precise mix and end volume. Unfortunately, no FC >30 and no decrease in CC. I’m perplexed.
-Bryan
 

frogabog

Gold Supporter
LifeTime Supporter
Jul 16, 2010
2,833
Portland, Oregon
Unless your tap water is from a well, it most likely has chlorine in it. You would have to use tap water that has sat out for 24hr in the sun to get an accurate result.

I'm not aware of this as an accepted method to save reagents.

Also, many municipalities actually add chloramine to the water instead of just chlorine.

How about giving us a pool water only test result. If you're not at 30ppm right now, you won't need to use 30 drops.
 
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frogabog

Gold Supporter
LifeTime Supporter
Jul 16, 2010
2,833
Portland, Oregon
I think we may have found the source of your high CC. I checked out the water information for your area, and assuming St. Paul is the only water supplier for the entire Twin Cities area, I found this:

Disinfection
Chlorine is then added to kill bacteria and virus. Free chlorine is in contact with the water for a period of time; then ammonia is added to react with the chlorine. This combined chlorine/ammonia compound is called chloramine. Chloramine is more stable than free chlorine, and allows for disinfectant to remain in the water even at the far reaches of our distribution system. Chloramine is also less likely to form unwanted disinfection by-products.