Drain & Refill Complete - DE Filter Cleaned - Next Steps?

[ViperGTSR6]

I just completed my drain and refill due to sky high CYA of 240 and want to SLAM the pool to eliminate mustard algae.

Here are my first readings on the freshly filled pool, the water looks clear and has no chemicals in it:

FC - 0
FC - 0
PH - 7.5
TA - 150
CH - 225
CYA - 0
Temp - 86 Degrees

To get ready for a SLAM, I believe I need to lower PH to 7.2, increase CYA to 40 and then add my chlorine. In what order do I need to do these things?

Thanks for all the help! I look forward to having a sparkly, balanced pool with the information I have found here!

 

[pabeader]

Use PoolMath to find out amount of CYA you need to add to get to 40. Put it in an old sock (one without extra holes Hang it in front of a return and squeeze it once in a while to help dissolve it. Or you could use the liquid CYA and not have to mess with it. Up to you and what is available to you.
Also use PoolMath to find out what you need to lower your pH. Usually folks use Muriatic acid

They can be done at the same time because the CYA takes a while. Also, it usually takes a week before the tests will show CYA so you assume it's in there and find your FC level for SLAMing from there.

 

[woodyp]

Why do you think you have mustard algae? You'd be surprised how many THINK that and really don't.

 

[ViperGTSR6]

Why do you think you have mustard algae? You'd be surprised how many THINK that and really don't.

Based on the description of mustard algae I was seeing a yellow accumulation on my shaded walls and when brushed it produced a yellow cloud. Now I am not so sure. I did discover Black Algae under one of the rocks of my waterfall while the pool was refilling. I scraped all of it off as it was very dry. I plan to brush those areas today to see if anything else comes off.

I was working on my chemical levels yesterday. I dropped PH to 7.2, I added 4 pounds of CYA to socks and positioned in front of return jets, and I added chlorine targeting 5ppm. When I went to bed at Midnight my levels were:

FC - 4.5
CC - 0
PH - 7.2
TA - 150
CH - 225
CYA - 20

I checked the pool this morning at 9:30 even after the pool had been exposed to direct sunlight and got the following readings:

FC - 3.5
CC - 0
PH - 7.2
TA - 140 (aerating with waterfall)
CH - 250
CYA - 30

Not sure if this counts as an OCLT but I did not lose more than 1ppm FC, CC is at 0 and the pool is clear. Should I bother with a SLAM?

 

[Richard320]

Based on the description of mustard algae I was seeing a yellow accumulation on my shaded walls and when brushed it produced a yellow cloud. Now I am not so sure. I did discover Black Algae under one of the rocks of my waterfall while the pool was refilling. I scraped all of it off as it was very dry. I plan to brush those areas today to see if anything else comes off.

I was working on my chemical levels yesterday. I dropped PH to 7.2, I added 4 pounds of CYA to socks and positioned in front of return jets, and I added chlorine targeting 5ppm. When I went to bed at Midnight my levels were:

FC - 4.5
CC - 0
PH - 7.2
TA - 150
CH - 225
CYA - 20

I checked the pool this morning at 9:30 even after the pool had been exposed to direct sunlight and got the following readings:

FC - 3.5
CC - 0
PH - 7.2
TA - 140 (aerating with waterfall)
CH - 250
CYA - 30

Not sure if this counts as an OCLT but I did not lose more than 1ppm FC, CC is at 0 and the pool is clear. Should I bother with a SLAM?

Yes. I'd expect the water to test nice since it's all fresh. But you KNOW you have algae spores in that pool. Kill 'em. Kill 'em all.

 

[ViperGTSR6]

Yes. I'd expect the water to test nice since it's all fresh. But you KNOW you have algae spores in that pool. Kill 'em. Kill 'em all.

So should I simply shock to the mustard algae level for 24 hours or SLAM? Im not sure how I would know when to stop a SLAM since all 3 of the criteria for stopping SLAM have already be met.

 

[JoyfulNoise]

For 40ppm CYA, your shock level of FC should be 16ppm. Why were you targeting 5ppm?

Just to be safe, I would elevate the FC to 16ppm and see how that holds overnight. That's what I would do.


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[Richard320]

So should I simply shock to the mustard algae level for 24 hours or SLAM? Im not sure how I would know when to stop a SLAM since all 3 of the criteria for stopping SLAM have already be met.

If you're satisfied that you passed the SLAM, then you proceed to the next step as noted in Pool School - Mustard Algae

To permanently get rid of mustard algae, you first SLAM the pool normally, following the directions in How to SLAM Your Pool. Once you have completed SLAMing your pool in the standard way, raise the FC level up to the extra high mustard algae shock level for 24 hours. Use PoolMath, or see the Yel/MstrdShock column in the chart in this post, to find your mustard algae shock level.

Personally, I think you're taking the literal view of things. "The water is clear" Okay, how about the walls? Are they clear? Still got black algae dots? Did you ever get to shock level? How can you say you passed the SLAM? You can't really say you finished it if you never started it.

 

[ViperGTSR6]

Ok I will elevate to shock level and monitor per the SLAM instructions. Then check the OCLT results in a day or 2.

I am still trying to make sense of all of this, thanks for the guidance.

 

[JoyfulNoise]

Ok I will elevate to shock level and monitor per the SLAM instructions. Then check the OCLT results in a day or 2.

I am still trying to make sense of all of this, thanks for the guidance.

You're doing great. Like riding a bike, it takes practice. After a season of practicing TFPC, you'll be an expert and your pool will be the envy of the neighborhood!


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[ViperGTSR6]

I brushed the entire pool yesterday. No yellow algae to speak of but did locate more black algae in some of the crevices in my rocks. As I scrubbed , I netted any visible pieces so that they would not be floating around the pool.

So last night I took another full set of tests:

FC - 3
CC - 0
PH - 7.5
TA - 140
CH - 250
CYA - 30

I added 4 pounds of CYA because that was all that my 2 socks would hold, per poolmath it should result in a CYA of 36 For the purpose of the SLAM I was targeting 16 for my shock FC since that was a little over my estimated CYA once it all dissolves and tests correctly.

9:00 PM
lowered PH to 7.2

9:30 PM
added 2 gallons of 10% liquid chlorine which resulted in a FC of 16.5 measured at 10:05 PM

11:20 PM
FC - 16
CC - 0

12:20 AM
FC - 16
CC - 0

6:40 AM (direct sun on one corner of the pool at this time)
Pool looks clear
FC - 14.5
CC - 0

I missed testing the pool without direct sunlight so I'm not certain of if the pool passed OCLT. What should I do from here? Keep up the SLAM for another day and run another OCLT tomorrow morning or assume it passed and bring the FC up to yellow mustard shock level?

 

[JoyfulNoise]

Keep up the SLAM. I doubt the minimal sunlight exposure caused any significant drop in FC.


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[ViperGTSR6]

I brought the FC back up above shock level.

8:00 AM added 47 ounces 10% chlorine

8:30 AM
FC - 17.5
CC - 0

9:40 AM
FC - 17.5
CC - 0

Im off to the store for more chlorine.

 

[ViperGTSR6]

1:20 PM
FC - 12.5 - added 80 ounces 10% chlorine targeting FC - 17
CC - 0

7:30 PM
FC - 12.5 - added 80 ounces 10% chlorine targeting FC - 17
CC - 0

10:00 PM
FC - 14.5 - added 45 ounces 10% chlorine
CC - 0

10:50 PM
FC - 17.5
CC - 0

I will try and test before the pool gets any direct sun to see if I pass an OCLT.

 

[Richard320]

You know....

 

[ViperGTSR6]

The pool is shaping up just in time for the Phoneix area to have 3-4 days of 113 degree heat.

6:15 AM
FC - 17.5
CC - 0

Passed the OCLT. Now to add chlorine to bring up to the mustard algae shock level of 24. Added 128 ounces of 10% chlorine at 6:20 AM.

7:40 AM
FC - 24.5
CC - 0


I threw in the brush, leaf bag, pole, turned the suction cleaner on, turned the waterfall on, and added all my pool toys to ensure they are exposed to the chlorine at shock levels too. I will maintain the chlorine level of 24 all day and brush the pool later today. Anything else I need to do?

 

[ViperGTSR6]

9:40 AM
FC - 20 Added 100 Ounces of 10% chlorine targeting 25 - 26

12:15 PM
FC - 15
CYA - 30
With a CYA of 30 I think the hot AZ sun is burning up my chlorine.

Since I am measuring CYA of 30, should I shoot for the mustard algae shock level of 18.2 or continue at 23.8 even though I added enough CYA to get to 36? I am not sure if 23.8 is sustainable with the sun/heat right now.