First SLAM

[jamie5879]

Hey there!

I did my first SLAM because my pool would not hold CL overnight and my CC was at 1 although the pool was crystal clear. I’m on day 2 and have a question. Last night my FC was at 15.5 and this am it is at 20.5 am I supposed to get up to 35 (SLAM level) and maintain that without any loss overnight?

Thanks!

 

[HermanTX]

Thanks for using Pool Math app and linking to your user name. It shows CYA of 90 and FC was 0 several days ago.
Did you add any LC after you tested at 15.5ppm - that data was not in the logs. What time did you test at both 15.5 and 20.5ppm?

SLAM requires to maintain your FC at 35ppm (CYA 90) so need to test every 4 hours. The OCLT test should not have a drop of more than 1 ppm. It would not increase unless there was a testing error or chlorine was added after a test.
Once you add chlorine, let it mix for 30 mins. Then test.
Maybe post a full set of data
FC
CC
CYA
TA
No need for pH or CH at this time.

 

[jamie5879]

I’ve just been testing chlorine during the SLAM and CC. My Cc went from 1 to .5. Sorry, new here and I need to upgrade my app so I’ve just been putting in the CL, I will do that now. 15.5 was yesterday at 6pm and 20.5 was at 6:30am today.

 

[HermanTX]

I’ve just been testing chlorine during the SLAM and CC. My Cc went from 1 to .5. Sorry, new here and I need to upgrade my app so I’ve just been putting in the CL, I will do that now. 15.5 was yesterday at 6pm and 20.5 was at 6:30am today.

Thanks for update. To confirm - you add chlorine at 5:30pm yesterday and allowed it to mix then tested at 6pm to read 15.5ppm. No chlorine added overnight and tested at 6:30am to read 20.5ppm.
Something is not calculating right - FC should not increase unless chlorine is added by some method. There are no floaters with chlorine pucks or no chlorine pucks in a inline chlorinator?

 

[jamie5879]

The test for 15.5 was before I added the CL. I tested at 6pm it was 15.5 FC and I added 3 gallons of 10% CL and this am the FC was at 20.5. I added 3 more gallons this am to bring it back up to SLAM level of 35. I won’t be able to test until I get home from work now :/

 

[SJPoe]

3 gallons LC at 10% in 19,000 gallons = 16ppm
16 (calculated add) + 15.5 (measured PM) = 31.5 (expected PM)
31.5 (expected PM) -20.5 (measured am) = 11ppm drop.

You need to keep slamming

Edit : And yes, the 'goal' is to maintain at or close to the slam level overnight, or at least, not lose any significant FC overnight when the only thing using up the FC would be algae/nasties.

 

[jamie5879]

Thanks! I’m testing 3 times per day right now, is that ok? Also, I know it says to disregard your PH during this but should I also be disregarding TA as well…..and is it safe to run my pool cleaner with CL this high?

 

[SJPoe]

The more often you can test, and the more you can keep topping back up to SLAM level, the quicker the SLAM will progress.
PH results will be skewed by the high FC level, which is why it is recommended to get the PH lowered before starting the SLAM process.

 

[HermanTX]

Thanks! I’m testing 3 times per day right now, is that ok? Also, I know it says to disregard your PH during this but should I also be disregarding TA as well…..and is it safe to run my pool cleaner with CL this high?

Disregard TA as well. Complete the SLAM and then adjust if needed.
Running pool cleaner will be fine. Assume it is pressure side or suction type cleaner. If it is robot - I would remove it.

 

[jamie5879]

Unfortunately with my kiddos sport schedules I’m just testing the pool now. I added a little more than the recommended bleach this am to use the rest of the gallon and my FC is actually at a 36 (my SLAM FC should be 35) so it looks like it held and stayed above after 12 hours with some sun mixed in. My pool is clear with maybe a slight haze to it but I might be the only one to notice it ha. I will see if I pass the OCLT in the am but is it ok to have a very slight haze? I also live on a dirt road and have dirt in my pool that collects on the ground. How do you know what’s dirt and what’s algae? Here is a pic of what I think is dirt…..it’s only ever on the bottom of the pool (not on the sides).

 

[HermanTX]

Unfortunately with my kiddos sport schedules I’m just testing the pool now. I added a little more than the recommended bleach this am to use the rest of the gallon and my FC is actually at a 36 (my SLAM FC should be 35) so it looks like it held and stayed above after 12 hours with some sun mixed in. My pool is clear with maybe a slight haze to it but I might be the only one to notice it ha. I will see if I pass the OCLT in the am but is it ok to have a very slight haze? I also live on a dirt road and have dirt in my pool that collects on the ground. How do you know what’s dirt and what’s algae? Here is a pic of what I think is dirt…..it’s only ever on the bottom of the pool (not on the sides).

I think many of us deal with fine debris (dirt) in pools. That is why we recommend to test every couple of days both FC and CC. Then if any concern do the OCLT as that tells you if its dirt or algae.
To end a SLAM the 3 criteria are
Once all three of these criteria are met, you have completed the SLAM process and can allow the FC to drop to normal levels.

• CC is 0.5 or lower
• AND your overnight chlorine loss test shows 1.0 ppm of loss or less
• AND pool water is crystal clear with no visible sign of algae (dead or alive) on floor and walls

 

[jamie5879]

Thanks! I was second guessing the crystal clear since the pool is clearing itself of dead algae and is cloudy but it has gotten less and less cloudy so hopefully crystal clear in the am

 

[jamie5879]

Hooray, done wit SLAM a few days back and everything going well! My PH is 7.5 but total alkalinity is still high at 200 (I did a partial drain and refill before SLAM as CYA was high which is why I believe the Alkalinity is so high as it’s been really low in the past.

In another post people mentioned not to worry about the alkalinity being high if PH was stable……just curious….why wouldn’t I want to adjust for the alkalinity down……wouldn’t that ruin my pool equipment leaving it high as well?