OCLT and SLAM

[mlaspina]

I think the wind is causing me to fail OCLT. I do a SLAM every May before swim season and usually pass OCLT in 2-3 days. Bad timing on my part - started my SLAM Wed. Have had winds up here EVERY NIGHT since. I've been steady at 2.0 Loss for the last 3 days, but wake up to a new set of debris in the pool, and a skimmer full of leaves and whatnot.

I'll keep at it, but think I'm gonna drop from mustard shock to regular shock level. I've not had CC more than barely pink - 1 drop clears it all in over 4 years of testing regardless of time of year.. Water did get that 'sparkle' back though on Sat, so I'm at 2/3. Maybe I'll get lucky and the wind will lay down before I have to go get another cart full of chlorine at Wally World.

Two questions:

1. Is mustard shock level overkill? No visible signs of Algae.
2. Anyone else have the wind mess up their OCLT?

 

[Mdragger88]

I think the wind is causing me to fail OCLT. I do a SLAM every May before swim season and usually pass OCLT in 2-3 days. Bad timing on my part - started my SLAM Wed. Have had winds up here EVERY NIGHT since. I've been steady at 2.0 Loss for the last 3 days, but wake up to a new set of debris in the pool, and a skimmer full of leaves and whatnot.

I'll keep at it, but think I'm gonna drop from mustard shock to regular shock level. I've not had CC more than barely pink - 1 drop clears it all in over 4 years of testing regardless of time of year.. Water did get that 'sparkle' back though on Sat, so I'm at 2/3. Maybe I'll get lucky and the wind will lay down before I have to go get another cart full of chlorine at Wally World.

Two questions:

1. Is mustard shock level overkill? No visible signs of Algae.
2. Anyone else have the wind mess up their OCLT?

1: If you suspect Mustard algae then you should fully complete the slam process (passing all 3 criteria) at normal slam fc level then proceed with MA slam level for 24 hours while also following all the other protocols listed here

Mustard Algae

Today We are going to show you how you can get rid of mustard algae in your pool. By following the steps in this guide and with no expensive chemicals.

www.troublefreepool.com

2: the wind no, organic debris yes if there’s alot

 

[mlaspina]

I decided to let it float down towards regular shock level yesterday and see. Debris from the wind seemed about the same, but it passed OLCT this morning. Chlorine consumption was quite high during the SLAM this time around (3 gal of 10% per day) - mostly during the sunlight hours. I attribute that to my low CYA level of ~32 and the intense sun my pool gets. So, I can't really attribute that to the overnight debris as it looked mostly the same today. I guess it's hard to pass OLCT at Mustard levels with a lower CYA.

Thanks for the heads up - after doing this for 20+ years, I never knew that you should SLAM at regular shock and then do Mustard levels after - I'll switch my routine next May. I don't see any signs of mustard or any algae, but like to make sure my annual SLAM gets EVERYTHING.

It's taken me 4.5 years to get CYA back to a level where I need to add some. When I moved in, it was > 100, so the previous owners must have got pucked over! Water back to sparkly with AZ extra high Calcium levels!

 

[Newdude]

I guess it's hard to pass OLCT at Mustard levels with a lower CYA

Its proportionate with FC @ 60% of your CYA and the OCLT removes the CYA buffering from the equation with no UV.

CYA 30 = MA FC 18
CYA 70 = MA FC 42.

Try making 84 perfectly perfect drops and see how far off you'd be with 70 CYA. 36 was evidentally too many. So we often recommend drifting down closer to target range to then remove the human error from the equation.

 

[mlaspina]

Try making 84 perfectly perfect drops and see how far off you'd be with 70 CYA. 36 was evidentally too many. So we often recommend drifting down closer to target range to then remove the human error from the equation.

Yeah, with FC up in the 20s, I ended up doing 2 tests each time (and 3 twice due to disagreeing readings on the 1st 2) to make sure I got the same reading. I may need to order a new bottle of drops sooner than I thought!

 

[Mdragger88]

You really aren’t meant to do an oclt at mustard algae fc levels.
That should have been done at normal slam levels. Along with passing the other criteria.
The ma fc level & procedures are just a “last nail in the coffin” thing.
If you suspect MA due to recurring issues at target fc levels then MA minimum should be maintained thereafter.

 

[proavia]

Living in the PHX area, you shouldn't need to do a SLAM every May.
Just maintain the pool in the off season just as you do the rest of the year. In the off season, it takes very little time and effort to do.

If you want to make your life even easier, consider installing a SWG to make your chlorine on site.

What is your current CH?
Does your autofill use hard tap water or soft water from a water softener?

One your FC gets down to 10 or less, post a full set of current test results.
FC
CC
pH
TA
CH
CYA
Salt (if you have a SWG)
Water temperature

Tell us a bit more about your pool by updating your signature with pool, all pool equipment (include manufacturers and model numbers) and test kit information.
Be specific with equipment.

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