First time SLAM. Need reassurance please.

[BKMoore78]

I’m a first time pool owner. Pool has been open a little over a month now and is crystal clear but I noticed I was going through chlorine very fast. Did the overnight chlorine test and got FC to 5 last night. Woke up at 5 am this morning before daylight and it was down to 1. Started my SLAM around 9:00 this morning. Added 5 gallons of chlorine to get FC up to 22 for my CYA of 55. I tested again 2 hrs later and it was down to 17 so I added another gallon plus. Then tested again just now and it was down to 16 so I added almost another 2 gallons. I guess I expected a drop in FC and need for chlorine but not this significant. Does this sound about right? I’ve brushed it good this morning and checked for hidden algae growth but see nothing. Not really sure why it’s dropping. Any insights could help. Thanks in advance.

Pool stats:
24,000 gallon Marcite plaster
FC 5
CC 0.5
pH 7.4
CYA 55
TA 70
CH 375

 

[Bperry]

I’m a first time pool owner. Pool has been open a little over a month now and is crystal clear but I noticed I was going through chlorine very fast. Did the overnight chlorine test and got FC to 5 last night. Woke up at 5 am this morning before daylight and it was down to 1. Started my SLAM around 9:00 this morning. Added 5 gallons of chlorine to get FC up to 22 for my CYA of 55. I tested again 2 hrs later and it was down to 17 so I added another gallon plus. Then tested again just now and it was down to 16 so I added almost another 2 gallons. I guess I expected a drop in FC and need for chlorine but not this significant. Does this sound about right? I’ve brushed it good this morning and checked for hidden algae growth but see nothing. Not really sure why it’s dropping. Any insights could help. Thanks in advance.

Pool stats:
24,000 gallon Marcite plaster
FC 5
CC 0.5
pH 7.4
CYA 55
TA 70
CH 375

The SLAM starts out pretty rough and gets easier as time goes by.

For reference, CYA is always measured in 10’s so your CYA is 60 and so your SLAM target is 24ppm.

 

[BKMoore78]

The SLAM starts out pretty rough and gets easier as time goes by.

For reference, CYA is always measured in 10’s so your CYA is 60 and so your SLAM target is 24ppm.

Thanks. I was using 22 per the PoolMath App but can start targeting 24 if that’s more appropriate.

 

[duraleigh]

I think you are doing everything correctly and your testing seems accurate. Invisible algae is daunting and sucks up the FC for perhaps as much as a day or so.

Continue your SLAM. The FC will begin to last longer and longer very soon. When your FC consumption slows to just 2-4 ppm daily, you will likely be able to pass the OCLT and that should end your SLAM.......assuming your CC's are .5 or less

 

[Deb04]

Thanks. I was using 22 per the PoolMath App but can start targeting 24 if that’s more appropriate.

Yes, use 24.

 

[BKMoore78]

Update…Spend all day testing it every 2-3 hours. FC levels dropped in morning readings by about 3 points per hour then 2 points per hour later in the day. I added chlorine last at 7:15 pm to get it back up to SLAM level. Checked it again at 9:30 pm and finally didn’t have any drop. Will check again tomorrow morning and see how it looks. So far, I’ve added the initial 5 gal of chlorine followed by about 6 more gal throughout the day. I plan on checking it one more time tonight then again first thing in the morning. Hopefully if it settles in overnight or at least slows down some. I won’t be able to check it as often tomorrow since I’ll be at work.

 

[Deb04]

Progress!

 

[BKMoore78]

AM Update:
Tested FC before sunrise this morning at 5:00. It dropped overnight from 24 to 20. Much slower than it had been yesterday, so it does appear the worst is behind me. Will try to run home during lunch today to test mid-day and again tonight. Then hopefully it'll pass the overnight test!

 

[Gotta Pool]

Awesome progress! Watch your filter pressures, too, those dead little plants gotta go somewhere...