Lost in my SLAM

[Green Goblin]

I've had a challenging pool month. My salt cell failed a few days before an 8 day trip, so I covered for that with liquid chlorine, and got the cell replaced. I returned to a pool that looked fine but was consuming a lot of chlorine and had mildly elevated CCs-- 1-2ish or so. I slammed with liquid chlorine, and it was an impressive battle-- I've been doing TFP for 10 years or more and have never seen a pool consume so much chlorine. The SLAM process has been imperfect, interrupted by storm damage, a medical procedure and a death in the family (it's been a heckuva month!). After a bit more than a week, the CCs trended up into the 5-7 range and became stubborn there, with the pool consuming about 3 gallons a day. The pool still looked great. I have had the pool cover off for the duration of the slam.

I tried to push the FC higher and added 6 gallons of 10% and the pool water seemed to get a slight yellow tint-- subtle, hard to tell with a French gray pool. About 5 years ago, I had an issue with iron staining after a high FC, so I backed off and let the FC drift back down. I felt lost at this point and decided to let the FC come down under 10 so I could get an accurate idea what my pH is and start again.

It took a few days to drift down below 10 and the pH was high, above 8, so I worked the pH back down to 7.4. The pool looks fantastic.

The CC had remained stubbornly high generally between 4.5 and 5.5. Last night it was 5, and I was wondering if I had gotten into a situation where I'd have to replace some of my water, despite looking fantastic. I rained like crazy last night, and this morning the CC is down.

Current numbers are:
pH 7.4 (tested yesterday night when FC was 9)
FC 14
CC 2.5
TA 60
CYA 50
CH 650

So, my questions are-- should I restart the SLAM process at this point? If so, what FC target-- I had been doing 24. Can I SLAM my way out of a CC over 5 with a FC of 24?

 

[PoolStored]

Very odd situation for sure. I would re-start the SLAM. Test and add chlorine every 1-2 hours in the beginning and keep at it. Your target should be 20 FC. No need to go higher. Higher FC doesn't help, it is about maintaining that 20FC .

 

[mknauss]

Those levels of CC are not seen unless chemically induced (sulfamic acid) or from direct ammonia (CYA degradation or ammonia based algaecide).

 

[Green Goblin]

Very odd situation for sure. I would re-start the SLAM. Test and add chlorine every 1-2 hours in the beginning and keep at it. Your target should be 20 FC. No need to go higher. Higher FC doesn't help, it is about maintaining that 20FC .

Thanks. I'll give it a try. I was using 24FC as a target because the pool was consuming very quickly (that seems to have settled down) and because sometimes when I check the CYA it's a bit over 50.

I have read about situations where folks use 10x the CC level as the FC target. I got my previous pool over 50FC once, but haven't gone there with this one, yet...

 

[mknauss]

CC - Further Reading

www.troublefreepool.com

 

[Green Goblin]

Those levels of CC are not seen unless chemically induced (sulfamic acid) or from direct ammonia (CYA degradation or ammonia based algaecide).

That is helpful to know-- I haven't put anything in the pool other than CYA, BiCarb, Chlorine, and Muriatic Acid. No algaecides ever.

A few months ago we had the pool cover company service the cover and it was clear that they used something to clean the cover with- the cover felt different and when I opened the cover I could see an oil like sheen on the water. I don't know if this could have been part of the problem.

As for direct ammonia, I suspect my youngest child has peed in the pool some-- we have a bathroom right next to the pool, and we tell them not to, but you know how kids are. CYA degradation is possible of course, but my CYA levels haven't noticeably dropped, though maybe I wouldn't have noticed.

Thanks for your help

 

[PoolStored]

Thanks. I'll give it a try. I was using 24FC as a target because the pool was consuming very quickly (that seems to have settled down) and because sometimes when I check the CYA it's a bit over 50.

I have read about situations where folks use 10x the CC level as the FC target. I got my previous pool over 50FC once, but haven't gone there with this one, yet...

If it is consuming it quickly, testing and replacing more often is the answer, particularly in the beginning...every hour until the FC loss slows is helpful. Higher FC level is not the answer, is wasteful and not safe for pool/equipment/people...

Do not use 10X, again not safe for pool/equipment/people.

 

[Green Goblin]

If it is consuming it quickly, testing and replacing more often is the answer, particularly in the beginning...every hour until the FC loss slows is helpful. Higher FC level is not the answer, is wasteful and not safe for pool/equipment/people...

Do not use 10X, again not safe for pool/equipment/people.

I'm happy to give it a try as recommended and we'll see where it goes. I'll report back, probably won't be able to do hourly checks until Saturday.

 

[Green Goblin]

Those levels of CC are not seen unless chemically induced (sulfamic acid) or from direct ammonia (CYA degradation or ammonia based algaecide).

Thinking a long way back-- when we had the iron staining 4-5 years ago. We used some Jack's magic, and did so regularly for a while, maybe 1-2 years. It's been a long time, last dose was more than 2y ago. I have done water exchanges since then, and would assume that much has diluted out. If I was getting a high reading from sulfamic acid the high reading would have been present previously as well, it wouldn't start now, years later, right?

My guess is that I just needed to be more patient and dedicated with my SLAM. and trust the process more.

 

[Green Goblin]

So I started a slam this morning, doing hourly checks.

Before starting numbers were:
pH 7.4
FC 7.5
CC 2
TA 60
CYA 50

I ordered a 50ppm CYA standard solution to make sure I was in the right range with the CYA before starting. The standard was a bit more cloudy than my pool water on the test, but only very slightly so.

the day has gone pretty much as expected for a SLAM- using a target of FC 20, FC readings ranged during the day from 24 to 18, with me adjusting the amount of liquid chlorine I have been adding in response. The CC numbers have bounced around a bit too-- went up to 5 from 2, then came down to 3, then back up to 5.

Here's what I don't understand:
6pm FC 19, CC 5, added about 1/2-2/3 gallon chlorine
7pm FC 26, CC 4.5, no chlorine added
8pm FC 18, CC 7.0

Dusk happened in the 7-8PM time period, and the pool filter kicked off for about 20 minutes in all of that, but the CC values-- I just don't have any experience with anything like this in my pool.

There is a part of this that makes me think I'm doing the testing wrong, because the results just don't seem to make sense. I've been using the TFT test kit for 10 years, and here I am re-reading the instruction card again making sure I haven't been doing it wrong for years.

 

[Green Goblin]

I added a gallon of chlorine at 8PM
9PM numbers: FC 22, CC 9.5

 

[newdude]

I am re-reading the instruction card again making sure I haven't been doing it wrong for years.

Yeah. Tell us your steps in detail.

 

[Mdragger88]

& clean your beaker with alcohol.
Also, scrub this cover you mentioned.

 

[Green Goblin]

Yeah. Tell us your steps in detail.

10ml of pool water is taken about 1 ft below the surface of the pool near one of the returns, but not directly in the flow of the return.

The water is tested in a vial used only for FAS/DPD chlorine testing, with a speed stir that is also used only for this test. They do look a bit grungy- my experience has been that this test tends to turn things a but grungy over time.

I add one scoop of R-0870 DPD powder (in this case the reagent, ordered from TFTestkits, arrived at my home less than 1 day prior to starting the slam) and start the speed stir.

I add R-0871 solution one drop at a time until it changes from pink to clear, and multiply the number of drops by 0.5 to obtain a FC reading (in this case the reagent, ordered from TFTestkits, arrived at my home less than 1 day prior to starting the slam)

Then I add 5 drops of R-0003 DPD Reagent #3, while stirring, (this reagent, ordered from TFTestkits, was received by me about 3 months ago)

I add R-0871 solution one drop at a time until it changes from pink to clear, and multiply the number of drops by 0.5 to obtain a CC reading

I will clean the vial and stir bar with alcohol, and also have a new vial and stir bar I can use too to compare.

Having experience with this test, I tend to add the R-0871 drops relatively quickly when doing the FC reading, I'll slow that down some and see if it makes a difference. I don't generally add the drops quickly when doing the CC reading, because usually it's not a lot of drops.

 

[Green Goblin]

This morning's numbers:
FC 27
CC: 8.5
CYA: 40

So, maybe some clues here-- maybe my CYA is being broken down, the CYA amount looks notably lower than yesterday-- I tried to do my CYA testing today at the same time as yesterday, standing in the same position, with clear skies both days. The difference in number from yesterday to today (50->40)doesn't tell the whole story, as we tend to round up the CYA reading to the next multiple of 10. The reality is that I'm having to add a good deal more to the tube today than I did yesterday to obscure the black dot. I'm going to test this again, if it's being consumed, should I add more to replace it?

One additional note is that the CCs didn't really jump up yesterday until around dusk and then dark. Maybe this is to be expected as the CCs should break down some in the sun?

 

[Green Goblin]

& clean your beaker with alcohol.
Also, scrub this cover you mentioned.

Will do on the beaker. Cover has not been on the pool for the past few weeks and was professionally cleaned about 2 months ago-- visibly it's the best it has looked in a few years. I can scrub it again, but I don't have a reasonable way to scrub the surface of the cover that would come in contact with the water if I were to use it.

 

[Green Goblin]

Also, will mention that I put brand new filter cartridges in the filter before starting the SLAM.

 

[Green Goblin]

& clean your beaker with alcohol.
Also, scrub this cover you mentioned.

You may have solved it-- it may have been the test vial or the spinner.

I had to take the kids to the shoe store, which took longer than expected, so I wasn't able to do hourly tests for a bit, but...

Old vial, at 10:30 FC 18 CC 8, added 1 gallon of chlorine
New vial, At 2:00 FC 22 CC 0.5 (almost 0, meaning just the faintest hint of pink), no chlorine added

I'm home for the rest of the day, so I can check every hour, and after some lunch I'll try to figure this out further and report back.

Thanks so much for the help.

 

[Green Goblin]

looking like it was a dirty test vial:

3PM
New vial: FC:22 CC:0
Old vial: FC:18.5 CC:8

I'll try cleaning the old one with alcohol and see if that gets a different result.

 

[Mdragger88]

You’ll be amazed at how clear it comes! Mine was so stained I couldn’t read the numbers until I cleaned it. Now I do it regularly- the stuff you don’t really think about ….