On day 4 of SLAM when a barely cloudy pool after pollen drop. We have cleaned our filters and the water is crystal clear but I check FC about every 3 hours during the day and we lose about 3-4 ppm....is it normal for the pool to be consuming that much chlorine still if water is clear?
SLAM questions
- Thread starter houston_tink
- Start date
No, if you are loosing FC that quickly, you either have algae or another organic consuming it or your FC/CYA ratio is not aligned and you are losing a lot to the sun. Can you post your current test results? Have you done an OCLT recently? If so, what is your overnight loss?
FC
CC
CYA
FC
CC
CYA
Readings at start of SLAM
FC 6
CC 0
PH 7.2
TA 50
CH 375
CYA 40
so my goal FC is 16.... here are my readings when I test. I then add chlorine to get back up to FC of 16. I did something wrong last night and ended up with a FC of 19
4/20
16 FC 1:30pm
10 FC 4:30pm
15 FC 8:00pm
4/21
13 FC 9:15am
16 FC 12:45pm
15 FC 3:30pm
13.5 FC 8:30pm
4/22
14.5 FC 7:00am CC 0.5
12 FC 12pm
13FC 5:15pm
12FC 9:00pm
19.5/19FC 11pm
4/24
16 FC 7:00am CC0.5
14.5 FC 12:30pm
12.5 FC 3:30pm
FC 6
CC 0
PH 7.2
TA 50
CH 375
CYA 40
so my goal FC is 16.... here are my readings when I test. I then add chlorine to get back up to FC of 16. I did something wrong last night and ended up with a FC of 19
4/20
16 FC 1:30pm
10 FC 4:30pm
15 FC 8:00pm
4/21
13 FC 9:15am
16 FC 12:45pm
15 FC 3:30pm
13.5 FC 8:30pm
4/22
14.5 FC 7:00am CC 0.5
12 FC 12pm
13FC 5:15pm
12FC 9:00pm
19.5/19FC 11pm
4/24
16 FC 7:00am CC0.5
14.5 FC 12:30pm
12.5 FC 3:30pm
Can you post a picture of your pool?
Overall, your numbers look like you are fighting something organic in the water. You are not doing a true OCLT (which is fine, but you may want to do one tonight just to see how much FC you are loosing without the sun as a factor), but it still seems like you are loosing more than 1 FC overnight indicating FC is being consumed by organics.
I would keep SLAMing, but since you say your water is crystal clear I think now is the time to start looking for algae hiding spots. Check any light niches, ladders, skimmer/weir door, if your pool has any additional features, make sure SLAM level water is running through them every day, make sure you are brushing everything in your pool at least once a day.
Just to make sure, are you adding/have you added and chemicals other than liquid bleach/chlorine to your pool recently?
4 days is not unheard of for a SLAM and it looks like you are seeing progress in that you started with cloudy water and now it's clear. If the algae is really bad, some SLAMs can take weeks.
Overall, your numbers look like you are fighting something organic in the water. You are not doing a true OCLT (which is fine, but you may want to do one tonight just to see how much FC you are loosing without the sun as a factor), but it still seems like you are loosing more than 1 FC overnight indicating FC is being consumed by organics.
I would keep SLAMing, but since you say your water is crystal clear I think now is the time to start looking for algae hiding spots. Check any light niches, ladders, skimmer/weir door, if your pool has any additional features, make sure SLAM level water is running through them every day, make sure you are brushing everything in your pool at least once a day.
Just to make sure, are you adding/have you added and chemicals other than liquid bleach/chlorine to your pool recently?
4 days is not unheard of for a SLAM and it looks like you are seeing progress in that you started with cloudy water and now it's clear. If the algae is really bad, some SLAMs can take weeks.
It is a super windy day here so hard to get a good pic. We have a black pebble bottom so water is always Dark. We are brushing 2X/day and have the dolphin M500 and filter pump and water features (spa overflow and Infinity edge) running 24 hours. Only thing added prior to SLAM was muriatic acid to get PH to 7.2see above for pic, but the 9:30pm to 7am reading last night....is that not a true OCLT?
The FC numbers should be the same from night to morning, with no CC and clear.
OCLT (overnight chlorine loss test) - you are loosing chlorine overnight.
You went from 19 to 16 to 14 to 12. So you were not maintaining the SLAM level. You have to keep it at target if possible through out the day until you stop loosing FC. FC below your target, which is 16, will prolong the SLAM. Then you can do the OCLT.
So actually you have not kept the SLAM and you will not pass the OCLT.
Keep up the SLAM.
OCLT (overnight chlorine loss test) - you are loosing chlorine overnight.
You went from 19 to 16 to 14 to 12. So you were not maintaining the SLAM level. You have to keep it at target if possible through out the day until you stop loosing FC. FC below your target, which is 16, will prolong the SLAM. Then you can do the OCLT.So actually you have not kept the SLAM and you will not pass the OCLT.
Keep up the SLAM.
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So actually you have not kept the SLAM and you will not pass the OCLT.
Keep up the SLAM.
so often should I check and add chlorine during the day to maintain at 16?
As often as you can, at least 3-4 times per day if possible. Each time you check it, if it's below 16, bring it back up to 16.
Notice your posted numbers on #3 post? How you brought it up to 16 and each test after that it dropped. That's when you make sure to get it back up again. Do this as often as you can during the day until it stops loosing FC so quickly. Then you can check FC less frequently until it holds steady, which will probably be a number of hours in between. Then you will be ready for the OCLT.
Once you get this straightened out, You will LOVE your sparkly beautiful pool!
CYA has no effect on how quickly FC dissipates overnight, Correct? In other words whether I have a CYA of 20 or 80 my FC should not drop more than 1ppm overnight?
So even if I misread my CYA and it is actually 30 instead of 40, FC would quickly trend down from 16 to 12 during the day but should stay at 16 overnight? It just seems like I can’t get my FC to stay at 16. Maybe I need to check dates on my reagents.
Your FC should remain (almost) constant overnight UNLESS you have organics (algae) in your pool which continue to consume chlorine. I am not sure you have a good grasp of the SLAM concept.