Did I run too close to min?

[offtheclock]

Thought I would be a pro this year. I guess not. Noticed the dreaded brown dust collecting on the seams, the steps and a couple dime size spots elsewhere yesterday morning. That evening there was more. TF100 testing shows my CYA was 60. Pool store showed 70. I brought it up to TF100 70 earlier this month. Since then I have been running 5-6 FC checking in the evenings with the occasional dip to 4 after having people over to swim. Never below 4. I run the salt cell at 40% for 11 hours during the day.

Decided yesterday afternoon to do a half slam and brought FC to 14 (28 would be SLAM level) for the evening. Did a OCLT last night. First test showed a 2 PPM loss and second showed a 1 PPM loss. Little to no CC. Brought FC back up to 14 before leaving for work. Just getting home at 5 and FC held all day at 14 but there was still the dust on the floor but not near as much. Has rained 2" from last night to today as well.

- Should I hold half slam and do another OCLT test tonight and see what happens
- Going on from here what should I maintain my FC at if 5PPM let this happen?
-Could pool store CYA be more accurate than my eyes on the TF100 test and could my CYA now be 80?
(Feel free to check my logs)

Thanks!

 

[Newdude]

Never below 4

*never tested below 4 (in the evening)

But. Huge mondo but.

It may have been 2 at 2 PM and the SWG picked it back up by the time you tested. We added a SWG range to the old chart this past winter specifically for this reason. SWGs swing too, just not quite as much as a LC pool would. The previous single digit target is now the low target, to allow a bit of wiggle room.



I target the 10 and if it overproduces a bit, so be it. I test for Ph when FC dips below 10.


If you see algae, do not pass go. Do not collect $200. Go straight to SLAM Process

Keep us posted.

 

[offtheclock]

OCLT showed a 1.5 loss last night. Went into full SLAM this morning. Lost around 3ppm from this morning to afternoon. Brought back up to estimated 28ppm for a CYA of 70 at lunch. There was very little dust this morning while brushing and again very little at lunch. Thought I would never be in this position again but here I am slamming. New liner installed 5 months ago too. Hopefully this will be a quick SLAM with no damage to liner.

Question: Do you lose chlorine faster during the day when the PPM level is high (28ppm) compared to normal operating range even if there is no algae?

 

[Newdude]

Chlorine burns off as a % so it does so faster at higher levels. Within normal operating ranges, the higher level FC burnoff is mostly mitigated by the higher CYA for SWG pools, but the extra burnoff becomes real noticeable in the 20s.

Right now, instead of losing 4 ppm to the sun, you may lose 5 or 6, plus whatever the algae consumed. Not that anyone wants to slam, but SWG folks really REALLY don't want to slam.

 

[Dirk]

Keep in mind that TFP recommended levels are meant to be a guide, which is just a starting point to determine what your pool actually needs. They are not in stone, and are not going to work the same in every single pool. There are just too many variables (size of pool, number of swimmers, weather conditions, yard conditions, fill water, testing methods, etc, is just a partial list).

Listen to your pool. It will tell you what it needs. If you got some algae in July/August by dipping to FC4, then your pool is telling you that FC4 is NOT its minimum. Simple as that.

That all said, like at least several of us, I use my recommended FC level as my minimum, and keep my "normal" FC at the upper end of the suggested range. That way, I never get anywhere near my actual minimum. If my pool dips below this "artificial" minimum, I immediately dose the pool back up above it.

If you play around too close to your minimum (your actual minimum), you are not leaving any "headroom" for an unexpected event: like a very hot day, or a few too many pee-ers in the pool, or one too many bird strikes, or a gust of leaves or a dead animal in the skimmer, etc. Even if FC4 is a legit minimum for your pool, it's based on normal conditions, not accounting for abnormal conditions, which Murphy's Law clearly states only occur while you are away or unable to check on your pool regularly. So...

Adjust TFP guidelines, as needed, to accommodate your particular pool, and then give yourself a little wiggle room.

 

[Newdude]

#teamrunhot.

The closer you are to minimum, the closer you need to watch it like a hawk.

I mock the algae looking for a way in.

'I know what you're thinking. Is the FC a 4, or an 11 ? Judging that this is an IC60, the most powerful SWG in the world, and it can blow your head clean off, I only have one question. Do you feel LUCKY ??? Well DO you PUNK ???'

 

[offtheclock]

Does anyone know how old this chlorine is? Just picked it yesterday and do not believe it to be effective. Brought pool up to shock level last night around 11pm and this morning I’m reading like I lost 11 ppm overnight.

 

[Newdude]

21 182 = the 182nd day of 2021. I do simple math with 30 days per month so that's 6 full months and 2 days. July 2nd 2021 (give or take a couple days)

It's pretty much salt water by now.

You want as fresh as possible, no more than 3 months old.

 

[offtheclock]

Yep I was afraid of that. Pool store got me. Sold me an entire case of that.

 

[Dirk]

That came from a pool store!?! That's outrageous. They know better, or should. I hope you take it all back.

For next time:

Chlorine Date Code Decoder/Easy Way to Measure Strength.

Hi, I just joined TFP this season and pool is looking great. TFP is an awesome resource. Thanks I thought the information below might be helpful for some of the forum participants. I recently bought 1 jug of 10% Liquid Chlorine that was actually 4.5%. It had a 2013 date code. I now am very...

www.troublefreepool.com

PS. Even three months can be too long depending on how it is stored (like in the hot part of the garden center at Lowes, for example). Plus you never really know how they stored it before it got there. End of season is the worst, because they've been restocking the top and the front of the pile all summer, so what's left in the fall could be years old.

I buy my chlorine from Leslie's. They are in a mall, so they store their chlorine indoors, air-conditioned. And they probably blow through so much of it that it's a safe bet it'll be fresher than anywhere else. Plus, I like to support the store. I don't buy much from them, but I don't want them going out of business, because it's good to have them around when I need them. With an SWG, I don't need much liquid chlorine per year, so I wouldn't be saving much, if any, shopping elsewhere for chlorine.

 

[offtheclock]

What did I do wrong? Well after aborting first attempt at SLAM because store sold me bad chlorine I waited a couple days and saw that I still needed to SLAM. Started again with good chlorine and held SLAM for 2 nights and 3 days before testing OCLT and passing 100%. Been letting FC fall back to my new target of 7FC (Previously was shooting for 5-6) and bam this morning i have dust on the floor and my FC was at 5.

 

[Dirk]

Maybe you stopped your SLAM too soon, and/or didn't eradicate hidden algae. Did you pass all three SLAM-is-over criteria? Do you know how to hunt down hidden algae?

 

[Newdude]

It's fall and nature is shedding again. Do an OCLT. I've had 'pollen' in my pool for a few weeks now.

Pass an OCLT and then you can rest easy as you wait it out. Or SLAM 2.0.

5 to 7 FC leaves you little wiggle room. If you aren't producing your entire days worth of FC during peak loss, your pool swings. If you produce FC off peak hours, such as overnight for electricity savings, or run 24/7 at a low %, the pool will swing more like a LC pool. I run 24/7 and swear by it. But mid day, the unit being on at 40% can't nearly keep up with the loss. It catches up overnight, but hours later.

Or the power flickers mid morning and you lose production that day while you're not home to see it. Or a big storm. Or a dozen other things. Or. It works until it doesn't, like recently.




For pools that swing you want to target the high end, or above.

Keep us posted on the OCLT.

 

[Dirk]

For pools that swing you want to target the high end, or above.

My pool doesn't swing and I target on the high end anyway. All of those "dozen other things" to which @Newdude refers can happen at any point in time. Whatever extra expense I might incur by running FC a little hot would be a pittance when compared to SLAMing my pool, for even a few days. I'm not even factoring in my labor. For me, slightly elevated FC is cheap insurance.

Did I already mention? (Too lazy to go look.) TFP recommended levels are guidelines. They don't, they just can't, account for every variable of every pool and its users. If you cannot control algae at recommended levels, after you've tried all the "normal" solutions, you just might have a pool that needs a higher FC. Simple as that.

 

[Bperry]

What did I do wrong? Well after aborting first attempt at SLAM because store sold me bad chlorine I waited a couple days and saw that I still needed to SLAM. Started again with good chlorine and held SLAM for 2 nights and 3 days before testing OCLT and passing 100%. Been letting FC fall back to my new target of 7FC (Previously was shooting for 5-6) and bam this morning i have dust on the floor and my FC was at 5.

There’s 3 boxes you have to check to pass a SLAM. OCLT is just one of them.

 

[Mdragger88]

Let’s start from the top

 

[offtheclock]

It's fall and nature is shedding again. Do an OCLT. I've had 'pollen' in my pool for a few weeks now.

Pass an OCLT and then you can rest easy as you wait it out. Or SLAM 2.0.

5 to 7 FC leaves you little wiggle room. If you aren't producing your entire days worth of FC during peak loss, your pool swings. If you produce FC off peak hours, such as overnight for electricity savings, or run 24/7 at a low %, the pool will swing more like a LC pool. I run 24/7 and swear by it. But mid day, the unit being on at 40% can't nearly keep up with the loss. It catches up overnight, but hours later.

Or the power flickers mid morning and you lose production that day while you're not home to see it. Or a big storm. Or a dozen other things. Or. It works until it doesn't, like recently.

View attachment 528603


For pools that swing you want to target the high end, or above.

Keep us posted on the OCLT.

Pollen was the culprit. It started off a little heavy and then lightened up. We even got pollen alerts on our phones from the weather app. Did another OCLT last night and passed with no FC loss and .5CC. I guess I was on edge from just coming off SLAM and did not think leaves are falling now.

 

[Newdude]

It gets me every spring and fall. The OCLT buys you another week or two of not worrying about it, and then it's over. Give yourself plenty of FC buffer above min so you don't worry that on day 6 it somehow became algae.