First time SLAM. Can I do it with CYA 28?

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aquamike

aquamike

Member
Jun 5, 2022
20
Wexford, PA
Pool Size
21232
Surface
Vinyl
Chlorine
Liquid Chlorine
I am going to SLAM my pool for the first time. The water is cloudy after my pump incident. Not green yet, but cloudy enough that I can't see the bottom of the deep end.

IMG_3318.jpeg
I don't have a FAS-DPD test. My local store only had the "HTH 6-way Test Kit" which includes an OTO test. I ordered a kit from TFTestKits.com, but that won't likely arrive for about a week.

I'm also a bit uncertain about my CYA level. The pool store's test reading was 28 ppm two weeks ago and I haven't added anything since. I used the CYA test from my HTH kit this morning and couldn't get a reading on the dot test (the solution was not cloudy at all).

What I do have is lots of liquid chlorine (8 jugs). Is there any point attempting to SLAM with a CYA of around 28?

I know raising CYA to a measurable level can take a few days. I don't really want to wait and then the algae gets worse. Also, school's out as of yesterday and the family is eager to get swimming so if I can just throw money at the problem (i.e. chlorine), I'll do it.
 
The 28ppm of CYA was measured by my pool store's test equipment. Not sure of the methodology, but they are a BioGuard dealer.

Using a "HTH 6-Way Test Kit" until the TF one arrives.
 
Pool store test results are not the most reliable (Example: Pool Store Experiment Water Samples)

Let's say we would use the pool store CYA test and assume a CYA of 30... if the test is wrong and your CYA is lower then the extra FC could bleach your liner while if it is higher it could be ineffective is killing alage.
There is also the issue on how you are going to Maintain the FC on a SLAM (Shock Level And Maintain) without being able to test on your own.
 
I've used the HTH 6-way test before and the CYA test is accurate. So if the dot was still visible with the tube filled all the way to the top, your CYA is under 10.

Go ahead and add enough stabilizer to raise it by 20 ppm and continue to add 5 ppm chlorine per day as advised until your kit arrives. This should hold things steady for now.

Your OTO test will measure TC up to 5, so if it's measuring less than 5 at any time, you can safely add more chlorine to bring it back to 5 as many times per day as you'd like. But unfortunately you can't go any higher right now without the risk of overdoing it.
 
Perhaps for now, but you will triumph in the end. How long after adding are you taking your measurement? Keep the pump running and measure about 15 minutes after adding and let us know what you get.
 
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Jeffchaps advice will diagnose if the % liquid chlorine you are using is as stated on the jugs.
If you get a solid rise in FC soon after the application then after 4 hours it is significantly reduced, you can diagnose for algae using an Overnight Chlorine Loss Test. Another possibility is your CYA is very low and the sun is chewing through the FC and you have an organic load.
 
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Until the FAS-DPD test comes in, you're driving with 20/200 vision - everything is blurry and you can't see exactly where you're going.

Keep adding 5ppm each day to the pool with liquid chlorine, and once the test comes in, we'll be able to tackle it without a blindfold on. Meanwhile check out this link that proavia provided earlier:

SLAM Process

And this video:



Once you have the kit, we'll clear it up with a SLAM. :)
 
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Keep at it - the system works. We just have to knock the algae down faster than it can multiply. Your FAS-DPD test will provide a lot more info once it arrives.
 
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After adding what seems like a staggering amount of chlorine, I finally got there this evening. TC 5ppm. :p

(Hope my cheapo test kits aren't lying to me and I wake up tomorrow to a bleached liner)
 
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A little late to the party but also make sure you are brushing and vacuuming too. If you have a robot, run that. If that ladder comes out, take that out and give it a good bleach scrub and do the same for any lights you might have.
 
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The TF test kit arrived yesterday. Did my first round of tests this morning. CL had gone down after I went a day without adding anything.

Couldn't get a reading at all on my CYA test. I added 2 lbs of stabilizer via sock three days ago. That's a lot less than the 8 lbs that PoolMath is recommending. I think I'll be off to the pool store to get some more.
 

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