Did I SLAM enough?

[steve_h]

No test results today, so the levels are approx.
SLAM'd pool to PoolMath Specs.
pH was 7.2-7.5
CYA was 30PPM at start.
SLAM'd to 12ppm FC per PoolMath. Brushed everything. Did this for 4 days, adding and adjusting chems as necessary.
The pool held 12ppm FC over night. I thought I was finished.
I have been adding salt to about 3000ppm and MA to counteract the 300ppm TA. But no CYA as I was waiting for the FC to drop to 2-5ppm.
I notice the pool has a slight green tint. The pool was clear following SLAM!

What gives?
Ideas.
Thanks.

 

[Bperry]

No test results today, so the levels are approx.
SLAM'd pool to PoolMath Specs.
pH was 7.2-7.5
CYA was 30PPM at start.
SLAM'd to 12ppm FC per PoolMath. Brushed everything. Did this for 4 days, adding and adjusting chems as necessary.
The pool held 12ppm FC over night. I thought I was finished.
I have been adding salt to about 3000ppm and MA to counteract the 300ppm TA. But no CYA as I was waiting for the FC to drop to 2-5ppm.
I notice the pool has a slight green tint. The pool was clear following SLAM!

What gives?
Ideas.
Thanks.

What are your current water test results?

 

[Bperry]

Oops, you have pool math logs which helps. Are they up to date?

3 days ago you had 1ppm FC and 2 days ago it was 11 after adding liquid chlorine. There no records of FC being 12ppm for very long. Maybe the logs just aren’t updated with everything? If the logs are accurate, you haven’t passed the SLAM criteria

 

[steve_h]

The way I read the SLAM...the pool was to hold the SLAM FC overnight.
Is this correct?
4/25 in the evening, FC = 11ppm. I added 1qt of 12.5% bleach to raise FC to 12ppm.
4/26 AM FC = 12ppm (ONCL = 0)
Since the FC held overnight, pool was clean and no Schmutz, I BELIEVED I met the SLAM!
To review:

You are done when:​

• CC is 0.5 or lower
• AND you pass an Overnight Chlorine Loss Test
  This test is intended to determine if your pool has a contaminant such as algae that is consuming chlorine. The test is performed by testing FC in the evening after sunset and again in the morning before sunrise. The readings will be the same if there is nothing in your water consuming chlorine.
  Synonyms:
  OCLT
  >OCLT (i.e. overnight FC loss test shows a loss of 1.0 ppm or less)
• AND pool water is crystal clear with no visible sign of algae (dead or alive) on floor and walls

When all three are true, you are done SLAMing and can allow the FC to drift down to normal levels.

What did I miss?

 

[PoolStored]

4/25 in the evening, FC = 11ppm. I added 1qt of 12.5% bleach to raise FC to 12ppm.

You are probably fine, but did you test after making the addition to confirm your FC was in fact 12 and not 13, 13.5 or 14? If you didn't test, you actually don't know your starting FC.

For insurance slam for 1 more day. When you test for OCLT, don't add any more chlorine, or add your chlorine and test 30 minutes later to start the test.

 

[Bperry]

The way I read the SLAM...the pool was to hold the SLAM FC overnight.
Is this correct?
4/25 in the evening, FC = 11ppm. I added 1qt of 12.5% bleach to raise FC to 12ppm.
4/26 AM FC = 12ppm (ONCL = 0)
Since the FC held overnight, pool was clean and no Schmutz, I BELIEVED I met the SLAM!
To review:

You are done when:​

• CC is 0.5 or lower
• AND you pass an Overnight Chlorine Loss Test
  This test is intended to determine if your pool has a contaminant such as algae that is consuming chlorine. The test is performed by testing FC in the evening after sunset and again in the morning before sunrise. The readings will be the same if there is nothing in your water consuming chlorine.
  Synonyms:
  OCLT
  >OCLT (i.e. overnight FC loss test shows a loss of 1.0 ppm or less)
• AND pool water is crystal clear with no visible sign of algae (dead or alive) on floor and walls

When all three are true, you are done SLAMing and can allow the FC to drift down to normal levels.

What did I miss?

It’s not just to hold the FC over night. It’s to hold the FC at SLAM level for however long it takes to get rid of any visible algae. It’s usually multiple days. Then when that’s done, you do an OCLT to make sure the chlorine level does not drop more than 1ppm. You need to test the FC at night AFTER all chlorine additions are done, then test again before the sun comes up in the morning. Maybe you did that but just didn’t record it? If the water turned green then that says something was missed. If you added chlorine after your test then that’s likely the problem. The pool math calculator just estimates and so you may have overshot the chlorine.

 

[steve_h]

Thanks,
My pool typically takes 5-6 hrs to turn over the water (27000gal/80GPM/(60min/hr) = 5.625 hrs.
I have not tested just after a chem add because I could get false readings based upon where I sample.
I usually wait some hours to let the chems circulate before a test.
How long do you guys wait?

Back to Square 1 ish.
Glad I did not add CYA.

Steve

 

[JJ_Tex]

When the pump is running, 30 mins after adding is plenty of time to properly mix everything and get accurate test results.

Turnover is not something you need to worry about... we can go down that rabit hole after you finish your SLAM.

 

[steve_h]

NNNOOOOO!
No rabbit holes nor PhD chemistry discussions. There are is a place called the "Deep End" for all of that...
They make my head hurt.
I am a Keep It Simple, Silly kinda guy!
But, thanks for the offer.
Steve

 

[Mdragger88]

For the
Overnight Chlorine Loss Test you must test to confirm your fc level after last addition.

 

[steve_h]

SO....after two additional SLAM days, the pool looks great.
Thanks for all the advice.
NOW, I cannot spill reagent all over the kitchen counter...Thankfully, it was clear.

Steve

 

[Mdragger88]

SO....after two additional SLAM days, the pool looks great.
Thanks for all the advice.
NOW, I cannot spill reagent all over the kitchen counter...Thankfully, it was clear.

Steve

If dpd powder was involved be sure to clean it up with something quickly or there will be black dots that appear later!
Have you passed the
Overnight Chlorine Loss Test?