SLAMing for green algae... a question about FC shock level before getting started


New member
May 4, 2017
Las Vegas, NV
Hi everyone! I have been a long time lurker. Thanks to all of you, I have managed to keep my pool sparking clean for several years up until recently...

Yesterday, I noticed green algae on the steps in my pool. I immediately brushed the entire pool and spent hours re-reading the pool school articles and various threads on here. This led me to go out and purchase jugs of bleach so I could begin the SLAM process. I tested for FC, CC, pH, and CYA and these are the results:

FC = 0.4 ppm
CC = 0.2 ppm
pH = 7.6 (added MA to drop it to 7.2)
CYA = 40

The problem I'm having now is with determining the appropriate FC shock level for my pool. I visited the Chlorine/CYA chart here: Pool School - Chlorine / CYA Chart

But, I have a SWG pool and the chart doesn't have any recommended FC shock levels for SWG pools with CYA <60.

Can someone please help me calculate the appropriate FC shock level for my SWG pool with a CYA reading of 40?

Thank you all in advance!

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Hello and welcome to TFP! :wave: Yes, when you have to SLAM, just treat the pool as a non-SWG pool since you're using bleach to SLAM anyways. So for a CYA of 40, your FC level should be "16". You can turn down (or off) the SWG to give it a break if you like and let the bleach do its thing. Great to have you here with us at TFP.