SLAM Pool Math

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Envieddesigns

Envieddesigns

Bronze Supporter
Apr 27, 2021
217
New Jersey
Pool Size
23000
Surface
Plaster
Chlorine
Liquid Chlorine
Hello to all,
I’m about to begin my slam process and looking at the pool math calculator under FC where it asks what type of sanitizer I’m going to use. I’m using 5 Gallon liquid chlorine Jugs from the pool store I choose bleach, then I put 12.5% chlorine which is what the jugs state on them but the last drop down asks what’s size jugs? The most you can put is 182oz though these 5 gallon jugs are 640 oz. ?
 
So my CYA is lower then 20 at least at 20 I could still see a little of the black dot at the bottom of the test tube through the cloudy water. My PH 7.8 and FC is 0. The pool calculator is saying to add 1 gallon & 2 quarts of bleach? Does it seem right? Do I start at this level them test later on in the day an proceed as such? Water is cloudy I can see a bit of the first main drain in the shallow side but not the drain on the deep end.
 
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Follow the SLAM Process. Please read the article. The CYA should be raised to 30 ppm. Then use 12 ppm FC for SLAM level.
Once you have started adding the additional 10 ppm CYA, raise your FC and test and add more liquid chlorine every few hours.
 
No idea how much you should add as you didn't list a bleach/chlorine percentage.
If the water is cloudy, chances are you may have a nascent algae bloom. You will need to do a SLAM Process

What testkit are you using?
Post a full set of current test results from one of the recommended testkits.
Consider performing an Overnight Chlorine Loss Test
 
Good evening,
The chlorine I’m using is 12.5%
Prior to doing anything my FC was 0 & CYA less than 20.
I put 1 lb of dry stabilizer in earlier today & 5 gallons of chlorine. Stabilizer was in the skimmer in a sock and I squeezed it every so often. There’s probably less than a golf ball size left.
at around 4:30pm
FC 7.5, CC 0.5, PH 7.5, CYA 20
At 10:15pm
FC 4, CC 0.5, PH 7.5, CYA 20
Do I just stay focused on getting the CYA to 30 before doing anymore Chlorine? Or do I just stay focused on getting the FC to 12?
Drop another 5 gal tonight or wait to retest everything tomorrow?
I have brushed three times and backwashed twice so far today PSI went above 10 psi twice today.
 
You want to maintain a fc level of 12 now & as often as possible but not more than once per hour. You can re test cya in 24hrs & then increase fc to the corresponding slam level for your tested cya if necessary.
 
Envieddesigns said:
Drop another 5 gal tonight or wait to retest everything tomorrow?
Click to expand...
5 gallons of 12.5% in your pool is 33 ppm FC. There is no need to raise the FC that high. Raise it to 12 ppm. Test and add back several times per day.
 
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You should follow the advice of TFP and add CYA using the sock method in front of a return. The problem now is that the CYA could be in your filter and be lost with a backwash.
For now, assume the CYA added is in the water and SLAM for that CYA level. Sounds like you’re at 30 CYA for a SLAM level of 12 FC. Test every two hours and add as much liquid chlorine to keep at SLAM level.
 

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Good evening,
So yesterday evening I continued the SLAM process. Last dose yesterday evening 11:19pm to bring up the FC to 14.
at 11:52pm I ran a test and got a reading of FC 13.5
At 5:49 this AM I checked and got a reading of FC 14 with a bit of cloudy water because my FC went to 0 yesterday while we used the pool.
during the day today the water cleared up well.
My FC has been dropping all day though is this normal? Also when I put the light on the water looks really cloudy near the light is that normal?
 

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Crystal clear water is step 1 of the three criteria to pass the SLAM. Looks like you need to maintain at SLAM level until the water clears.
 
Use the filter. Typically you can always vac to the filter unless you have large amounts of solid debris.
 
Here’s an updated photo, big difference now with clarity with the light on. I dosed 12oz Bleach at 6:42pm because I was at 11.5 and at 9:29 it was at 12.5 FC. Going to check in another 30 min see if it needs another dose before calling it a night to recheck in AM.
 

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At this stage 3 or 4 times per day is sufficient to test FC and add liquid chlorine, if necessary.
 

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