A pool that hates chlorine

[FrankieKat]

Today, the cover was closed for all but about 3 hours during the day (for the swim time above), and between 7:15am and 7:45pm we lost 6ppm so about 0.5 ppm / hour.

Will repeat OCLT again tonight. Fingers crossed!

 

[Mdragger88]

Your cya is 50 which is about as high as you want it to be in a manually chlorinated pool so it’s the liquid diet going forward for your pool.
Here’s roughly what each dissolved puck does to your water

You will have to determine going forward whether or not you can tolerate any pucks & how many. You can see that they increase cya at a pretty quick pace.
For most people they don’t increase fc quickly enough to replenish the average 2-4 ppm per day losses while also keeping fc up with the ever increasing cya they add. YMMV.
If you wish to use them you will have to be vigilant.

 

[FrankieKat]

ll repeat OCLT again tonight. Fingers crossed!

Okay, looks like we lost about 1 ppm overnight (9pm-7am) with cover open. Seems like we're mostly there but think I'll just try to keep the SLAM level (25 now) going until I leave.

Your cya is 50 which is about as high as you want it to be in a manually chlorinated pool so it’s the liquid diet going forward for your pool.

Understood. That's such a shame that it adds so nyc CYA because it is convenient to have something that trickle adds chlorine routinely.

most people they don’t increase fc quickly enough to replenish the average 2-4 ppm per day losses while also keeping fc up with the ever increasing cya they add.

I assume when I keep the cover closed I won't see losses as large?

 

[drsipe]

View attachment 515135

Now that is sparkly water,,,, excellent.

If you pass all three criteria for ending the SLAM, I would say you have been successful.

1. clear water
2. pass an over night chlorine loss test, loss of 0.5 or less chlorine loss over night
3. 0.5 or less CC

 

[FrankieKat]

1. clear water

Yes!

2. pass an over night chlorine loss test, loss of 0.5 or less chlorine loss over night

Cautiously optimistic about that. Only reason for that is it feels like when you're talking 49-50 drops of the 871 there's possibility for error (miscounting a single drop or not being 100% certain whether or not the vial color is colorless or ever so slightly pink).

Tonight I will do it again but this time do 3 separate tests before and after just so I can feel a bit more confident in the consistency of the results.

3. 0.5 or less CC

Yes!

Thanks again everyone!

 

[BDY]

After i let my FC drop from 28 to mid teens I passed my OCLT. The high FC was just too wide a testing variance. I kept getting 1.5-2 difference over a few days despite all other criteria so i let it drop and retested. YMMV

Re the cover - there are pros and cons. It helps with chlorine loss and temperature loss but lets CC build up so you have to open cover routinely to let the sun do its works. (That’s my simple understanding)

 

[FrankieKat]

After i let my FC drop from 28 to mid teens I passed my OCLT. The high FC was just too wide a testing variance. I kept getting 1.5-2 difference over a few days despite all other criteria so i let it drop and retested. YMMV

Makes total sense. Not exactly sure if this is how it works though, but 25 to 24 is only a 4% drop so would that be in line with a 10 to 9.6 drop or a 1 to 0.96 drop?

Re the cover - there are pros and cons. It helps with chlorine loss and temperature loss but lets CC build up so you have to open cover routinely to let the sun do its works. (That’s my simple understanding)

By routinely, how often do you mean (once a day, twice a week, etc)?

 

[BDY]

Re drop - it’s same criteria as OCLT, but the testing variance in size of drops, counting error, etc is much less. So a difference of 1.5 at high FC may be due to organics or may be due to testing variance. If due to organics you would have the same 1.5 drop at lower FC.

Re cover - someone else with more experience will have to answer that one sorry

 

[Mdragger88]

Okay, looks like we lost about 1 ppm overnight (9pm-7am) with cover open. Seems like we're mostly there but think I'll just try to keep the SLAM level (25 now) going until I leave.

Great plan

Understood. That's such a shame that it adds so nyc CYA because it is convenient to have something that trickle adds chlorine routinely.

Convenient but insidious…
A stenner/liquid doser
Or a swcg don’t have those side effects.

I assume when I keep the cover closed I won't see losses as large?

Correct slam level fc + the cover should have you, well… covered for your time away lol

 

[Newdude]

My cover needed to be opened weekly. The exact timage fluctuated a little. If you go too long, you'll know when you open it and it smells like a public pool. No harm done, and it burns off in a minute or two if the sun's up. Open it a bit sooner the next time.

 

[FrankieKat]

Or a swcg don’t have those side effects.

It sounds like I have a bit more research to do on SWCGs. I have a dead pool heat pump that needs a compressor (meaning a new unit) so perhaps that might be a better investment than replacing that.

 

[kul]

I keep my pool covered with solar cover. This is to conserve chlorine and decrease evaporation. With the cover on my FC drops about 2-2.5, without it 4. When I use the cover, I can go about 10 days without topping off with water. If I don’t use the cover it would be 5-7. The spa area is not covered. I only remove a little bit when adding chlorine or MA. Usually on the weekends I leave it off when we are going to swim. Never had any issues with this method. Try and see what works for you.

 

[Bperry]

Makes total sense. Not exactly sure if this is how it works though, but 25 to 24 is only a 4% drop so would that be in line with a 10 to 9.6 drop or a 1 to 0.96 drop?

By routinely, how often do you mean (once a day, twice a week, etc)?

Keep an eye on it once the cover is back on. More than one person found their cover was contaminated and causing the problem.

 

[FrankieKat]

Keep an eye on it once the cover is back on. More than one person found their cover was contaminated and causing the problem.

Yeah, that's one of the reasons I'm interested to try and see if it changes anything.

So today, with the cover closed all day from 7:15A - 5:00P, the level dropped to 18 ppm FC, so a loss of 6 ppm. Interestingly, this is the exact same drop I saw yesterday with the cover open for about half the day. It's been a pretty hot and full sun day today.

Does that sound reasonable, given the SLAM level or suspiciously high?

 

[Bperry]

Yeah, that's one of the reasons I'm interested to try and see if it changes anything.

So today, with the cover closed all day from 7:15A - 5:00P, the level dropped to 18 ppm FC, so a loss of 6 ppm. Interestingly, this is the exact same drop I saw yesterday with the cover open for about half the day. It's been a pretty hot and full sun day today.

Does that sound reasonable, given the SLAM level or suspiciously high?

So you lost the same amount of chlorine with the cover closed but only for half the day? Kinda hard to draw a hard conclusion.

 

[Mdragger88]

Did you scrub this cover? And clean its pit?

 

[FrankieKat]

Did you scrub this cover? And clean its pit?

I don't even know how to access the pit, so no. It's probably going to be pretty disgusting. This sounds like a good job for #PoolStore! Lol

I assume it would be just as important to clean the underside of the cover but don't see how that would even be possible. Seems like having the bottom soak in the SLAM water might take care of some of that, no?

Overnight between 9:15p and 7:15a I lost 3 ppm. Both times I did the test twice and seemed pretty consistent (50 drops and you're going to have some error). But what's a little odd is that when I measured at 5:00p I got 18 ppm, then I added 1 gallon of 10% (calculator says that should add 5.5 ppm) and when I retested it at 9:15p I got 24 ppm, which is actually 1 ppm higher. So either that's the variance in my testing or I've miscalculated the volume of the pool. It's 32' x 16', with 6' deep end and 3' shallow end not counting stairs, so perhaps it's closer to 17,000 (though that would only be the difference between 5.6 and 5.8 per gallon).

Long story short, I plan to keep up the SLAM level as long as I can. If it's just a matter of adding a gallon a day until we're totally 100% sure it's clear, it's doable.

 

[BDY]

Am i missing something? 24 minus 18 is 6, and you were expecting 5.5? I would call that acceptable rounding

 

[FrankieKat]

Am i missing something? 24 minus 18 is 6, and you were expecting 5.5? I would call that acceptable rounding

Yeah, agreed it's not much.

Today, cover on from 7:15am to 6pm and lost about 5.5 ppm, which is the same as it's been the past three days where the first day it was open all day, the second open half the day and today closed all day. Hmm...

Going to keep on keeping on!

 

[FrankieKat]

So between Friday night and 12:30pm, with the cover open I lost 5.5 ppm which is 0.3 ppm / hour so very good considering it was open during the morning!

Between 12:30p and 8:30p the cover was closed and I only lost 0.5 ppm *total* (I tested twice both times!).

Added two bottles to bring it up to 33ppm and having the cat sitter add a gallon twice during the week (was a bit too much to train her to do the Taylor test).

Fingers crossed!

Thanks again for all the help and advice!

FK