Advice on shocking a green pool & followup?

Antlo

Well-known member
Apr 23, 2024
67
North Carolina
Pool Size
19200
Surface
Vinyl
Chlorine
Liquid Chlorine
I'm back! I got a lot of great advice the first time I made a post a few weeks ago when opening our pool for the season. At that point I added baking soda for alkalinity and CYA while using Liquid chlorine to maintain FC levels.

However, we had about 4-5 days of heavy rain a week and a half ago and I'll admit to missing a few days of adding chlorine (this is my first pool ever, did not know that was a huge mistake! now I do.). It led to a green pool that looked similar to opening season, yuck. After trying to get it back with a vacuum and normal amounts of chlorine I realized we needed to shock again. That is what I did on Friday, two days ago, and now the water is finally slowly changing from green back to blue. I added 4lbs of dichlor over about 36hours, testing frequently and making sure chlorine levels were high. The initial shock I put in got used up by the next day when I tested, so I added more to maintain that high level.

CYA - 40
Alkalinity - 80
pH (just tested) 7.2, added a box of borax so should be back in range now, will test

I have a Taylor K2006 test kit being delivered tomorrow, finally bit the bullet.

My question is; the pool is at a teal color at the moment and still cloudy. Chlorine level is about 5ppm which is nowhere near shock level for my amount of CYA, but it's been about 36 hours since that initial shock and the bit of followup I added. Do I need to keep chlorine levels at slam/shock level until the pool is clear, or will that 4lbs clear it up overtime?

I am aware of the chlorine overnight loss test but I don't think I can complete that correctly until my test kit arrives tomorrow. I was hoping to have a semi-clear pool for swimming this weekend so wanting to do this whole shock/slam thing correctly and not cut any corners. Any advice is appreciated, as soon as my test kit comes tomorrow I will post my levels. Just want to make the most of today in terms of clearing it up!
 
Do I need to keep chlorine levels at slam/shock level until the pool is clear,
Yes, Follow the SLAM Process. Read the article.

Add 5 ppm FC worth of liquid chlorine today and every day until you get your test kit. Then run a full set of pool water chemistry tests when you get your kit. Then follow the SLAM Process
 
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Stop using "dichlor" as it's dumping more CYA in which you do not want now. If you have a CYA of 40 you need to use liquid chlorine and follow poolmath for the slam level needed.
Gotcha, well I've used all I had on hand so that's that now :ROFLMAO: Will test CYA accurately tomorrow when I get the kit, hopefully it's not too high as I already feel like it takes too much liquid chlorine to maintain.
 
IMG_0253.jpgIMG_0261.jpg

Went from ugly green to teal, can see through the shallow end completely. Going to be repeatedly adding liquid chlorine today to maintain shock levels until my test kit gets here tomorrow & determine if I need anything else adjusted. Progress at least!
 
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Random question for anyone reading, do you recommend using a Hayward Navigator (hose/suction) type vacuum while the pool is in this state of "clearing up"?

Just wondering if using the vacuum results in overall less circulation since the floor drain is closed 3/4 of the way when using a skimmer-connected vacuum. Is the vacuum hindering the circulation process, or helping the situation?
 
The long anticipated test kit has arrived and I have immediately conducted my first set of tests.

I am currently slamming the pool based on my previously thought numbers which weren't too far off. The pool changed from green to blue since Friday and is now just cloudy and working on getting that last bit out of the deep end. Hoping it continues to clear up by tomorrow. Just looking to see if I need to adjust my approach any given these results:

Using Taylor K2006: (FAS-DPD for Cl)
Free Chlorine: 15ppm (took 30 drops!)
Combined Chlorine: 0.5ppm
CYA: 50 (this one's a bit questionable, you could still barely barely see the black dot. if needing to be completely invisible I would say closer to 40, but rounded up)
pH: 7.8
Total Alkalinity: 90
- Question about this one; is it the exact second of color change or when the red color is intense? Color changed exactly at 9 drops so I said 90, but more intense red would've been a few drops more)

I previously thought my CYA to be 40, so I held SLAM at 16ppm. Now that I'm thinking 50, I need to increase Cl to 20ppm, right? Anything else that I need to change to perfect my water?

Should I go ahead and test Calcium Hardness as well? I thought I heard it wasn't really a big deal but no clue.

Thanks!
 
Focus on FC levels during SLAM. Once you pass the three criteria to end the SLAM, then run a full suite of tests (FC must be below 10 ppm for pH test to be valid) and post them here.
 

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Focus on FC levels during SLAM. Once you pass the three criteria to end the SLAM, then run a full suite of tests (FC must be below 10 ppm for pH test to be valid) and post them here.
Since my CYA was never tested after addition of liquid stabilizer, I would assume that test is pretty pertinent, no? Is the CYA test accurate with a Chlorine level of 15ppm?

I just added enough chlorine to raise FC to 20ppm based on those results, or was that a mistake?

edit: sorry about making a new thread btw, idk why I didn't just comment here. Thanks for moving!
 
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Only test effected by FC levels is the pH test.
Your CYA test of 50 ppm should be used for your SLAM.
 
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General rule of thumb for swimming after a SLAM? Just wondering if once we have clear water we're good to hop in, or if we should wait for FC numbers to decrease back to normal maintenance levels. We're not there yet, just curious. Hopefully another 24-48hrs!

Blue water this morning, almost no green to be seen! Deep end still cloudy & can't see the bottom but making progress each day. Hopefully now that I have SLAM level correct for my CYA the process will move along a bit faster. FC was 18.5 this morning so I added enough to get her to 21ppm & will try to hold there throughout today.
 
Jeez, sunlight really eats your chlorine. Tested at 9am this morning 18.5ppm, added 1/2gal to get me to 20-21ppm (slam level for 50cya).

Just tested at 1pm, 15.5ppm. Assuming that 1/2 gal got me to 20, 5ppm loss over 4-5 hours pretty normal? UV levels are extreme today, no clouds, straight sun!

No matter, I've added 3/4gal to get me back to slam level (for now...)

Question about CC's; if getting a cc result of 0 from FASDPD test, does this mean no algae is present? Or could it test 0 now and then 4 hours later test higher? Deep end's still cloudy, so guessing still algae or at least clearing dead algae, just curious how to interpret CC correctly!
 

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