SLAM timeframe while passing OCLT & 0 CC?

offtheclock

Silver Supporter
Dec 30, 2020
290
Greenville, SC
Pool Size
13500
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Hate to be posting again. At the end of the season last year I was getting what I assumed was a algae dusting on the floor. I performed a SLAM before closing and passed OCLT and had clear water for several days before settling on a FC of 11 and CC of Zero with no dust. From there I put the cover on. Opened up yesterday after 3 months to a sparkling clean pool with no dust, 10FC and still zero CC. Just added salt and tested all other levels. Today just one day later I have the dust on the floor again! I guess I need to SLAM but for how long?? I was passing OCLT and water is crystal clear. How long should I run a SLAM to make sure this is gone? As soon as I SLAM the dust will be gone but I do not want it back this time. CYA is 80 now unfortutnally.

Dust 1.jpg
Dust 2.jpg
 
There is no set timeline for a SLAM. When the algae quickly comes back after passing the SLAM exit criteria typically means there is hidden algae somewhere.

Typical hiding spots are:
- Stairs
- Ladders
- Weir Doors
- Behind lights
- Auto fill valves
- Water features

Have you thoroughly scrubbed and checked each of those as they apply to your pool? Stairs seem to be the worst on above ground pools and sometimes must be removed and cleaned outside of the pool.
 
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First, verify it's really algae with an OCLT. Things other than algae can look like dust on the bottom.

Construction kicking dirt in the air has been reported here.

Fwiw, here's my weird one: after hard rain, my pool ends up with hundreds of earth worms on the bottom. When they disintegrate before I can get them scooped up, the residue looks like algae, but OCLT passes fine. Strange but true.
 
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Pollen season is starting in the warmer areas.

Crops are being planted in those areas too which kicks up farm dust like construction would.

If you pass an OCLT with flying colors, it's environmental and not algae. Opening with 10 FC yesterday and not being below min since makes me put my wager on environmental.

:epds:
 
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When I opened pool Monday the FC was at 10 and CC at 0. This was some where around 2pm. Just went out this morning and FC is at 9 and CC .5 I have not added any chlorine yet. I will do a OCLT but i suspect I will pass as I have only lost 1 FC over a day and a half. I also check skimmer doors for algae and they are all clear. Ladder was removed for winter.
 
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I will do a OCLT but i suspect I will pass as I have only lost 1 FC over a day and a half.
You kinda sorta passed already. But make it official. (y)

Also, this happens to me every spring and fall. The trees and farms shed late season dust that isn't pollen, but might as well be.

Every time I wonder, I OCLT and then I feel better for a week or two. If it doesn't stop, I run another. If I wasn't already running hot, I would raise FC a little while the dust was happening.
 
you may consider doing the Mustard algae protocols after passing all 3 criteria this go round to cover all the bases. Be sure to check all nooks & crannies as well!
{light niches, steps (inside & out), drain covers, ladder handrails, skimmer throats/weirs/weir door foam, abandoned lines, autofill, overflow drains, seam flaps, etc.}
*If water can go there, algae can thrive there.

 
you may consider doing the Mustard algae protocols after passing all 3 criteria this go round to cover all the bases. Be sure to check all nooks & crannies as well!
{light niches, steps (inside & out), drain covers, ladder handrails, skimmer throats/weirs/weir door foam, abandoned lines, autofill, overflow drains, seam flaps, etc.}
*If water can go there, algae can thrive there.

Would mustard algae comsume still consume chlorine? I mean could I pass OCLT and still have mustard algae. This dust is only settling on the sunny side of the pool where the returns are blowing it.
 

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Would mustard algae comsume still consume chlorine? I mean could I pass OCLT and still have mustard algae. This dust is only settling on the sunny side of the pool where the returns are blowing it.
Yes you could- one of the hallmarks of it is the return of its presence after fc returns to normal yet sufficient range for your cya.
It is generally “gone/invisible” at slam fc levels.
I suspect you only have regular algae & just need to continue filtering & slamming but was suggesting this extra step after this slam is completed since you seem to have had a reoccurrence after completing slam in the past. It offers peace of mind for some rather than waiting for reoccurrence.
Try some pool grade de in the sand filter to help catch those finer particles & you’ll probably be passing all 3 criteria soon since the crystal clear no algae dead or alive is your last hurdle for regular slam completion. If you have the pleated filter for your bot that will help too.
 
Ok update. There was the dust when I got home but very light. There was some of it sitting in the throat of my skimmer and around the edge of the skimmer basket. It had a gritty feeling to it before puffy away. Could this be coming from my filter or does it seem environmental?
IMG_8294.jpeg
 
Could this be coming from my filter or does it seem environmental?
It could be one, the other, or both.

I've often wondered how many SLAMs we've extended for another week with dust being the only reason to continue. All those spring SLAMs will also have all kinds of crud blowing in but it all looks the same.

Keep tabs on it and with no unexpected FC loss, I'd let it ride for now. Bump the FC just in case and at it'll likely be gone in a week or so. If by some chance it isn't, you kept it at bay in the meantime and aren't worried about a swamp.

It took me some years to accept that I had similar in the spring and fall and all I could do was wait it out. That was with a heavily oak-d property and now we moved next to a farm with different crud blowing in but the same end result. Your season gets going before mine so you're pretty much right on schedule. It held 10 FC on its own all winter so that's one heckuva OCLT.
 
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Still holding FC and passing OCLT. Sometimes zero CC sometimes barely .5. Dust seems to be getting a little worse. Do not see any pollen on any of my furniture. Thinking I am going to SLAM. With passing OCLT and the FC only dropping around .5 a day with no additions how long should I hold a slam for?
 
Still holding FC and passing OCLT. Sometimes zero CC sometimes barely .5. Dust seems to be getting a little worse. Do not see any pollen on any of my furniture. Thinking I am going to SLAM. With passing OCLT and the FC only dropping around .5 a day with no additions how long should I hold a slam for?
Until you meet the crystal clear - no algae (dead or alive) criteria along with passing the oclt & cc’s of .5 or less.
 
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Still holding FC and passing OCLT. Sometimes zero CC sometimes barely .5. Dust seems to be getting a little worse. Do not see any pollen on any of my furniture. Thinking I am going to SLAM. With passing OCLT and the FC only dropping around .5 a day with no additions how long should I hold a slam for?
So you are passsing 2 out of the 3 criteria to end the SLAM, but since you are visually seeing evidence of algae you don't pass all 3 criteria.

See my post #2 about hidden algae as I suspect that is your issue. Likely still have algae hidden in some random spot that isn't enough to see on the test results, but you can still see the dead algae as dust. Find that algae and give it a good scrub so the SLAM level chlorine can finish it off and let you get back to normal.
 
So was 100% algae. Did a four night SLAM and passed OCLT perfectly 2 nights in a row and saw zero dust. Been letting FC drift back down. Was at 17 yesterday and 0 CC. Started to sea the slightest amount of dust on two of the seams. I am talking razor thin for about 2-3'. On the seam only. Wondering if I should bring back up to SLAM level again or if this still could be some residual being killed off or passing through the filter.
 

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