Keeping FC up during slam


Jun 22, 2017
I am doing my first SLAM for mustard algae. Target FC is 25. I started yesterday and tested 4-5 times throughout the day. Every time I check FC, it is well below 25ppm. I know it's going to drop, especially during the day, but should I be adding enough bleach to overshoot my FC target so it doesn't dip below 25? If I test more often, I'm afraid I will run out of reagent before the SLAM is finished. Also, would it be better to keep the SWG on to help keep FC level up during SLAM? Thanks for any help.


LifeTime Supporter
Aug 18, 2014
Amelia Island, FL
In this instance, you would continue adding multiple times per day. Being a bit over doesn't hurt, but don't be fooled that it will decrease your SLAM time. More is not necessarily better.


Mod Squad
TFP Expert
Platinum Supporter
LifeTime Supporter
In The Industry
Apr 1, 2007
Sebring, Florida
txnole offers great advice. Your FC loss will start to decrease and you can safely drop to testing twice daily now.

Going over the 25 ppm SLAM value by a little (say 28 ppm) is OK but remember these guidelines were developed to make sure there is no unintended consequence.

(If 2 aspirin is great, wouldn't 16 aspirins be 8 times better?)

DO NOT TURN ON your SWG. Keeping track of your FC loss is essential, the SWG wipes that out


TFP Expert
LifeTime Supporter
Jan 6, 2010
San Dimas, CA (LA County)
For Mustard algae, first you SLAM normally. Then you raise it to Mustard level for a day. So until things clear up, you probably don't need to go so high on the FC.

See Pool School - Mustard Algae

And running out of reagents is probably more common than not, which is why I always push the TF100 with the XL option. The first tub of powder is for the SLAM, the second is for the rest of the season. You can get refills here.