Is it better to slam at lower CYA

santacruzpool

Gold Supporter
Feb 24, 2015
622
Santa Cruz, CA
If it was me, and I needed to SLAM, then I would do it while the CYA is "low" - that means you need to have a lower FC target level during your SLAM which should be a little easier with the CYA at 50 - CYA is not the problem to focus on at this point.

Get the PH to 7.2 and then start the SLAM by getting some liquid chlorine in there - the sooner the better!

Once you have completed the SLAM then you can bump your CYA up to the SWCG TFP Target of 70.
 
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justinc

Gold Supporter
Apr 3, 2019
508
Texas
When you are SLAMing, you turn the SWCG off and treat your pool as if you chlorinate with liquid chlorine. If you have already adjusted your CYA that is OK, but you are fine to proceed with a SLAM at 50 (and it will make things easier if you are still at 50 because your shock target is lower).
 

Bordertown

Member
Jun 19, 2018
22
Nova Scotia
I have adjusted the PH finally I had it too high then too low in the last 24 hrs (overshot too much muriadic acid then too much borax). I am at 7.4 PH now.
Yesterday I added stabilizer and got to 50 CYA so I added a bit more stabilizer an hour ago.
So I just dropped 2 gallons of 10.8% of bleach chlorine to get started 5 minutes ago
 

justinc

Gold Supporter
Apr 3, 2019
508
Texas
I have adjusted the PH finally I had it too high then too low in the last 24 hrs (overshot too much muriadic acid then too much borax). I am at 7.4 PH now.
Yesterday I added stabilizer and got to 50 CYA so I added a bit more stabilizer an hour ago.
So I just dropped 2 gallons of 10.8% of bleach chlorine to get started 5 minutes ago
Since you added stablizer to take you OVER 50... you will need to use that new projected CYA level (50 + whatever you added) as your target chlorine level for your SLAM
 

Teald024

TFP Guide
Pool math is telling me to slam at 26 so I need to go add 2.6 more gallons of bleach on top of the 2 I added 20 minutes ago
Yeah, add the additional chlorine. Follow Shock FC column in the FC/CYA Chart. A lower CYA would have been better and easier. If the CYA is in a sock, go pull it out of the pool.

Next time you adjust the pH, don't do the roller-coaster method of raise & lower. Start with smaller additions until you get to where you want to be.
 
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