New SWG pool owner, about to start SLAM

Jump to latest Follow Reply
R

riverwind91

Gold Supporter
Jul 5, 2024
14
Michigan
Bought a house last summer and ended up with a pool. Seller said it's a salt water pool, really simple, nothing needs to be done.
So I did nothing in a year other than hired a company to close and open. When closing the pool last fall, I added quite some well water to bring water level back, and that was when the water started to look yellowish and I thought it's iron from well water.
Fast forward to this year, pool was opened, water looked clear with a little yellow color at deep end, and nothing about the water was done. Kids used the pool for a few weeks and I could see the water has becoming cloudier every time.
That's when I started to question the 'no maintenance' comment. I've added a couple bags of salt to the pool, and added three bags of those powder shock a week ago.
Also I found TFP, bought the TF100 test kit, and ready to SLAM.
Did first water test an hour ago (it was fun), here are the results:
FC: 4.5
CC: 1
pH: 7.8
TA: 300
CH: 250
CYA: 0
Salt: 3800 (vs SGW panel consistently reading 3000)
Plan to do another test tomorrow morning to make sure there's no testing mistake, then I will proceed to SLAM.

Attached is a photo of how it looks now. Will log how it looks like as SLAM goes.

Meanwhile, I have a couple questions if any folks can share some insights:
1. During SLAM process, should I turn off water heater? (SLAM process doesn't specify about heater)
2. Do you all keep pool cover off for the entire season? How about those of you who have automatic safety cover? I've been closing the cover every time after use so it's been closed most of the time
3. Do you think having the pool covered all the time ended up affecting chemical levels? I could see the cover helps to retain FC, but will restrict aeration therefore resulting in high pH. How come my TA ends up so high?
4. Looks like the first step of SLAM for me will be lowering pH by adding muriatic acid. Should I worry about the high TA at all?
5. I will add CYA to 30ppm. with FC at 4.5, I assume I won't need to add liquid chlorine initially until FC drops below 3, am I right?

Thank you all in advance!
 

Attachments

  • IMG_9519.jpg
    IMG_9519.jpg
    510.7 KB · Views: 18
Welcome to TFP! :wave: In preparation for the SLAM Process:
1. SWG off
2. Lower pH to around 7.2 - 7.4 with muriatic acid; don't worry about the TA right now. We can address it later.
3. Add stabilizer for a CYA goal of 30; use the sock pre-socking method.
4. Using liquid chlorine, increase (and maintain) a SLAM FC level of "12".
5. Leave the cover off until you complete the SLAM (pass all 3 criteria).

From that point forward, your priority is FC testing and doing your best to stay around the FC of 12. Follow all the protocol listed on the SLAM Process and it will work itself out. If you have any questions let us know.
 
Welcome to TFP.
Thanks for purchasing the TF100 test kit as that is perfect to do a SLAM.
Please print out and reread SLAM Process

First - get your CYA up to 30ppm. You need to protect the chlorine you add for SLAM.
Next - lower pH to 7.2 using muractic acid
3rd - buy liquid chlorine and prepare to increase FC level.
The SLAM level FC is 12ppm for a CYA of 30ppm. If you CYA goes to 40 then SLAM FC is 16ppm
The key is to MAINTAIN that FC level of 16ppm so plan to test every 3 or 4 hours during the day and top up with liquid chlorine to keep FC at 12 or 16 depending the CYA level.
For 21k gals, 1 gallon of liquid chlorine (10%) will raise the FC level by 4.8ppm - add 1 gallon per day until your CYA is confirmed at 30 or higher.
After you add stabilizer to increase CYA, test again after 48 hrs to confirm that you reached 30ppm or if it went higher.

Do not put the cover on the pool during a SLAM. It is best to remove it if you can and clean it with household bleach. That can hold algae.
Also a cover retains CC so best to open it occasionally when the pool is properly balanced after the SLAM.
No need to keep heater on.
TA is increased through fill water or by addition of soda ash. Test your fill water to determine the level of TA in it.
 
HermanTX said:
....
First - get your CYA up to 30ppm. You need to protect the chlorine you add for SLAM.
...
The SLAM level FC is 12ppm for a CYA of 30ppm. If you CYA goes to 40 then SLAM FC is 16ppm
The key is to MAINTAIN that FC level of 16ppm so plan to test every 3 or 4 hours during the day and top up with liquid chlorine to keep FC at 12 or 16 depending the CYA level.
For 21k gals, 1 gallon of liquid chlorine (10%) will raise the FC level by 4.8ppm - add 1 gallon per day until your CYA is confirmed at 30 or higher.
Click to expand...
Thanks for the detailed reply!
Follow up question: you mentioned bringing CYA to 30ppm, then add liquid chlorine to raise FC but need to add 1 gallon per day until CYA is confirmed to be 30+. Meaning, the added liquid chlorine has a chance to lower CYA as well?
May I assume that CYA and Chlorine molecules will bond with each other, therefore adding FC will actually cause CYA level to be lowered? Also, the way CYA protects chlorine, is it also due to this bonded molecule which can release chlorine when chlorine level is lowered?
 
Texas Splash said:
Welcome to TFP! :wave: In preparation for the SLAM Process:
1. SWG off
2. Lower pH to around 7.2 - 7.4 with muriatic acid; don't worry about the TA right now. We can address it later.
3. Add stabilizer for a CYA goal of 30; use the sock pre-socking method.
4. Using liquid chlorine, increase (and maintain) a SLAM FC level of "12".
5. Leave the cover off until you complete the SLAM (pass all 3 criteria).

From that point forward, your priority is FC testing and doing your best to stay around the FC of 12. Follow all the protocol listed on the SLAM Process and it will work itself out. If you have any questions let us know.
Click to expand...
Much appreciated!
First time for me to hear about sock method for adding CYA, checked TFP further and understood CYA is slow to dissolve therefore using a sock as container for dissolving CYA into pool water. This is important to know and I'd have missed it you didn't mention it.
 
riverwind91 said:
Follow up question: you mentioned bringing CYA to 30ppm, then add liquid chlorine to raise FC but need to add 1 gallon per day until CYA is confirmed to be 30+. Meaning, the added liquid chlorine has a chance to lower CYA as well?
May I assume that CYA and Chlorine molecules will bond with each other, therefore adding FC will actually cause CYA level to be lowered? Also, the way CYA protects chlorine, is it also due to this bonded molecule which can release chlorine when chlorine level is lowered?
Click to expand...
The purpose of adding 1 gal of LC was to keep the pool from getting worse while you add CYA. LC does not lower CYA. Only draining water from the pool will lower CYA.
If you have CYA on hand, and can add enough to get to 30, then the SLAM process can start using CYA of 30 and FC of 12. I would retest CYA in 48 hrs to ensure it did not go to 40 and if it did, then you need to increase FC to 16ppm for CYA 40.
Print out the SLAM Process and read it several times.
 
HermanTX said:
The purpose of adding 1 gal of LC was to keep the pool from getting worse while you add CYA. LC does not lower CYA. Only draining water from the pool will lower CYA.
If you have CYA on hand, and can add enough to get to 30, then the SLAM process can start using CYA of 30 and FC of 12. I would retest CYA in 48 hrs to ensure it did not go to 40 and if it did, then you need to increase FC to 16ppm for CYA 40.
Print out the SLAM Process and read it several times.
Click to expand...
got it, buying CYA and liquid chlorine tomorrow!
 
  • Like
Reactions: HermanTX
Added 1 gallon of HCl, got pH to about 7.3. Can see slight improvement of clarity in pool.
Added 3-4 lbs of CYA using sock method. Added 1 gallon of liquid Chlorine. Will do another full test of water tomorrow night and start SLAM, assume no more CYA is required.
 
Last edited:

Enjoying this content?

Support TFP with a donation.

Give Support
riverwind91 said:
Added 1 gallon of HCl, got pH to about 7.3. Can see slight improvement of clarity in pool.
Added 3-4 lbs of CYA using sock method. Added 1 gallon of liquid Chlorine. Will do another full test of water tomorrow night and start SLAM, assume no more CYA is required.
Click to expand...
You can start SLAM in morning if you have added sufficient stabilizer to reach 30ppm CYA. It may take time to register on a test but assume CYA is at target and raise FC to 12ppm
 
HermanTX said:
You can start SLAM in morning if you have added sufficient stabilizer to reach 30ppm CYA. It may take time to register on a test but assume CYA is at target and raise FC to 12ppm
Click to expand...
Had to go to work today, only able to start SLAM this evening.
Before SLAM, did one more test, got CYA at about 20, FC was 7. Water is visibly better than before and I can see the Dolphin robot at deep end of pool.
Added 1 gallon of HCl, and added the remaining 1 lbs of CYA in sock. These two addition should be able to bring pool to SLAM level of FC 12ppm and CYA 30
Will test again tomorrow evening. Working from home on Friday and will be able to add chlorine every 3 hours that day.
Attaching two photos of water today, quite happy about how quickly it has improved even before reaching SLAM level.
Have also subscribed to PoolMath app. $7.99 a year is very reasonable and you guys are awesome.
 

Attachments

  • IMG_9524.jpg
    IMG_9524.jpg
    684.8 KB · Views: 10
  • IMG_9530.jpg
    IMG_9530.jpg
    698.9 KB · Views: 10
Last edited:
Tested again, FC 11.5-12, CYA 40-50
Think I have over-shot CYA, like Herman said, CYA had registered slowly. So my real CYA level might be around 50 now, will check again tomorrow.
Added another gallon of liquid Chlorine targeting 16ppm FC, also pulled the wet sock (with undissolved CYA crystal) out of skimmer. Will put it back once SLAM is completed.
Need to buy more liquid chlorine tomorrow noon, then test CYA again to decide if FC needs to be further increased and maintained tomorrow afternoon. Will do OCLT tomorrow night, plan to do Saturday full day high FC level and OCLT, too.
 
Last edited:

Enjoying this content?

Support TFP with a donation.

Give Support
You must log in or register to reply here.
Thread Status
Hello , This thread has been inactive for over 60 days. New postings here are unlikely to be seen or responded to by other members. For better visibility, consider Starting A New Thread.
Top Bottom
Back
Jump to latest Follow Reply