Deciding if I should SLAM or not

DigitalOcean

Active member
May 2, 2017
43
Lawrenceburg
#1
My water is crystal clear, but this being my first year on TFP, I am closely monitoring my chlorine levels.
I have come along way in the past two weeks. I started with an estimated CYA of 120 (half pool water and half tap water to 7ml mark then 7ml of R-0013; water level was at 60 ~ CYA:120) when I started out After getting the CYA under control, I am focusing on Chlorine and making sure all algae and bacteria are killed in the pool.

All that being said, I'm not sure if I should SLAM or not. Last night around 9:00pm I added bleach to get my FC to 9.5.
This morning at 4:45am, my FC was 5.5 and the pressure was up on my sand filter ~25%.
Since then, I have backwashed and added more bleach to bring FC back up to 9.5.

I am letting my filter run 24/7 and maintaining 9.5 FC levels today (Checking every couple of hours) but not sure if I should go ahead and do the full SLAM or not.

Reading through other post, I can say the FC consumption are not from hidden algae in steps or lights as there are no lights in the pool, and the ladders and hand rail have not been setup yet.

I have also read the Chlorine / CYA Chart and for my CYA of 50, my target FC is between 6-8, so I am keeping my chlorine just above that so FC doesn't settle below the minimum.

FC 9.5
CC 0 (Why is CC not on the Pool Math App by the way?)
pH 7.2
TA 70
CH 200
CYA 50

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Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
#2
Last night around 9:00pm I added bleach to get my FC to 9.5. This morning at 4:45am, my FC was 5.5 and the pressure was up on my sand filter ~25%.
This statement seems to answer the question - SLAM. Loosing 4 ppm overnight is simply too much. Shoot, we don't like to see that much loss over 24 hrs which includes the sun's UV. The pressure increase tells us your filter is working overtime against organics material you simply cannot see. The sooner you start the SLAM the sooner you'll get done. By the looks of things, it shouldn't take incredibly long. You have a very nice looking pool. Good job on the proper test kit, adjusting yoru CYA, and managing things properly. You're doing it the right way. :goodjob:

PS ~ The reason you don't see CC on the chart is that it's not something we adjust directly. CCs are a by-product of the oxidation process as your free chlorine attacks contaminants in the water. It can fluctuate slightly based on those actions and the available UV light. It's more of an "indicator" or alarm to us rather than a chemical we adjust. Hope that helps.
 
Apr 22, 2017
19
Southern Indiana
#5
Newbie here, but I have been lurking in the forum shadows for a few weeks now and I have come to the realization that if you are asking yourself if you need to SLAM bc of the math, then you probably do ;) Your pool looks really nice!
 

domct203

Bronze Supporter
LifeTime Supporter
TFP Guide
Jun 3, 2015
3,959
CT
#8
Is your filter/pump running 24/7? Are you brushing?


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DigitalOcean

Active member
May 2, 2017
43
Lawrenceburg
#10
Last Night (9:30pm) FC - 21.5
This Morning (5am) FC - 19.5

So I have lost 2ppm overnight, and according to the OLCT test, I need to keep SLAMing. The pressure on my sand filter over the past 24 hours has only gone up about 2 PSI. Hopefully tonight will be the final night.
 
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DigitalOcean

Active member
May 2, 2017
43
Lawrenceburg
#12
I agree. Maintain the SLAM and hopefully this will be a short-lived process. Also, I couldn't tell from your pic above, but if you have a light, you might consider pulling it out to look behind for algae. Very common hiding place. Have a nice day!
Thanks Texas for the support. I vacuumed the pool this morning which had a few leaves, but thats about all. I do not have any lights. Could algae be hiding somewhere else? Is it possible Algae could be inside my return jets?

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Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
#13
Wow, that water sure looks good. :goodjob: We don't see algae in return jets all that often unless the pool sat un-used for a long time. Removing jets sometimes opens-up a new can of problems. :hammer" Since you have nothing else in the water that could hold algae, I'd let the SLAM do its thing today and give the OCLT another shot tonight/tomorrow and see how much you lose. If it fails again, the only thing I can thing of is perhaps a good deep cleaning of the sand. As clear as your water looks now though, I'd leave that as a last option.
 
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DigitalOcean

Active member
May 2, 2017
43
Lawrenceburg
#14
Same story, just a different day. Last night 9:45 FC - 18. This morning 4:30 FC - 16. However the pressure gauge hasn't raised in 2 days.
I am tempted to clean out the sand filter, but am not convinced this is the issue.

THEORY: If I put the multi-valve on "Recirculate" instead of "Filter" at night, I should be able to test the water overnight and see if it does drop any. Correct?
If the pool doesn't drop any PPM overnight on recirculate, then the sand filter needs to be cleaned.

Does this sound right to you guys?
 

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
#15
THEORY: If I put the multi-valve on "Recirculate" instead of "Filter" at night, I should be able to test the water overnight and see if it does drop any. Correct?
If the pool doesn't drop any PPM overnight on recirculate, then the sand filter needs to be cleaned.
Hummm. Well, it sounds like a possible way to isolate a problem. But in your pool, with absolutely nothing else in the water, it sounds like that must be the culprit.

Or, you could simply give this whole process a day or two and monitor so you don't get burnt-out. We start to get obsessed with testing, drips, water levels, and all sorts of stuff. Occasionally, testing variances play a part as well. I would say do what you feel comfortable trying as long as you keep your sanity. :crazy:
 

woodyp

Mod Squad
TFP Expert
LifeTime Supporter
Apr 17, 2010
10,235
East Texas
#17
If you simply MUST do something, I'd advise just doing a deep clean of that sand filter. You risk damaging those delicate laterals by taking it apart, emptying, and refilling with sand. NOTHING is growing in there. Maybe your SLAM just finally caught up.