Starting a Slam and Wondering What Happened

[RLP]

Adding stabilizer will not prevent FC from dropping overnight. You need to add chlorine daily.

post a complete set of test results.

read up on the slam procedure, you need to slam untill you pass the 3 criteria. Crystal clear water being one of them.

 

[treyrich]

@RLP thanks for your response, definitely glad for all the help provided by TFP. Just for clarity I have extensively studied the slam procedure, and have executed one recently (see the previous posts in this thread) to great success. I *believe* that I have a pretty strong handle on the TFP methods, and while I am still new here I spent the last year reading as much of the site as I possibly could in preparation for my pool being finished.

I understand that adding stabilizer will not prevent FC from dropping overnight, however that wasn't my question, it is my hypothesis that adding stabilizer is somehow consuming my FC. That said I am willing to admit that this could be a giant coincidence, but my troubles with CYA retention documented here in this thread are contributing to my thoughts. Of course chorine needs to be added daily, my SWG is running and was keeping up great with my consumption until I added the stabilizer (hence my suspicions).

As for the test results, you can click on my profile to see all of my pool math logs, but here are my tests from this morning for what that's worth, however I don't know that they're relevant to my question(s)?
FC 6
CC 0.5
PH 7.4
TA 90
CH 275
CYA 50

 

[koffey]

Flipping through your logs, you went from cya of 0 to 30 without logging anything that was added... How did you get that number when it was zero?

 

[treyrich]

That was after the pool builder’s guy added some stabilizer, but I didn’t know how much he added, so I didn’t log anything on the addition. That was the only addition that I didn’t make personally, so that’s the only one not logged.

 

[treyrich]

He did make an off handed comment to me that he “added a couple of pounds of stabilizer”, but I still didn’t feel that was enough information to accurately log

 

[koffey]

A couple of pounds (2lbs) wouldn't get your cya to 30 in a pool that big. Anyways.... The only thing that I can see from a loss or little net gain of cya is as was pointed earlier, ammonia. Did you test for it?

 

[treyrich]

I didn’t. The FC only hit 0 the one time when I was out of town, and before it was said that it could be ammonia I had already dosed up to SLAM. Since then I’ve been running my FC really hot in an effort to avoid another SLAM. But apparently I wasn’t running hot enough?

Best I can tell last night I lost about 2.5 FC (I didn’t turn off my SWG so that’s my guess based on the SWG output + loss experienced). So that means I’m going to have to start another slam as soon as I can go buy more bleach. I’m completely baffled and a little discouraged on how this could happen though, I test every single day (sometimes twice a day), my FC even when it dropped this time was on the high-side of the scale. I get that last time something caused my FC to go to 0 because I was out of town, nothing I could do there, but this time it feels like I’ve done everything exactly right and by the book, but somehow the result was the same as being out of town and ignoring the pool for a week?

 

[treyrich]

Some additional thoughts to attempt to track down what happened here:

1. My family is at the beach every day, I am literally writing this right now while touching the ocean. There basically isn't a day where someone isn't in both the ocean and then the pool afterwards. We always make the kids shower off any sand on them before getting in the pool, but we're not "sanitizing" people or swim suits. I have a hard time believing this could be much of an issue given that we were always well above minimum FC, but perhaps it is a factor?
2. I have 4 kids under the age of 9, so I'm certain that a decent amount of urine is making it's way into the pool despite my best efforts, could this be a factor? Again I would think that my level of FC should be taking care of this with no big deal at all, but maybe not?
3. My confidence level on my ability to read the CYA test is basically 0. I have already burned through 6 oz of reagent in 2 months trying to get it dialed in. I am as sure as I can be that my levels are what I've recorded in Pool Math (as of this morning it was just over 50 so round it up to 60), but is it possible that I've completely botched that test to the point of my FC not being effective enough due to the CYA levels?
4. I have a bypass valve that is cracked open for my heatpump (but not my gas heater), is it possible that I don't have it cracked open enough and there's not enough flow moving through the heat pump which has caused stagnate water to fester in there and grow something (I didn't think this was possible being that it gets no sunlight, but maybe)?

Short of these factors I am really drawing a blank as to what could have happened here. Before (earlier in this thread) it was easy to point at the pool builder and say that some of the sand he introduced into the system caused the issue. But this time the only thing that went into the water was bleach, muratic acid, cya, fill water, maybe some bird poop, and people. The first drop I noticed where the SWG wasn't addressing the FC usage was going from 11 -> 9.5, then I didn't change anything to see what would happen and it dropped again from 9.5 -> 6 and so then I started supplementing with bleach.

Long story short, I completed a slam 9 days ago all criteria clear, the lowest my FC got was 6 and that was yesterday. The water is clear (though just on the cloudy side of clear). And I am ripping my hair out (or I would be if I had hair) trying to figure out how I could have prevented this from happening because I thought I was doing everything right.

 

[RLP]

What % are you running your swcg at? Does the "cell" light come on to indicate that it is making chlorine?

It should be off for a period of time, them on for a period of time, dictated by the % selected.

They do make a "standard" for the cya test to demonstrate what 50 Ppm is. R-7065 CYA Standard 50ppm (2oz)

 

[treyrich]

SWG is working, "cell" light comes on and off and when on I can see small bubbles from returns, it's a brand new cell. Percentage is set at 30% when cover is closed and 60% when cover is open currently. I've been trying to get it dialed in and this seems like it was pretty close to what I needed before whatever is happening now started up.

I'll order some of that standard solution. That shipping cost is a killer though haha!

 

[treyrich]

SLAM started this evening, and topped off again to 24 FC tonight.

 

[Pauls234]

Cya doesn't really get consumed by anything at quick rate other than the bacteria we see that leads to ammonia, but that is pretty rare in a cared for pool, it's usually the swamps that haven't been opened for a year or 3. The tell tale signs are Cya at zero and FC getting consumed almost instantly when you add it (like in 20 min or less first dose) so doesn't seem to be the case here.

As we all know, cya is the most difficult and frustrating test to do and there also can be a lag time of up to a day or 2 before it shows up on the test. Have you watched the videos or come across some the tricks people do around here to make it more repeatable? Looking at the side of the vial, fill til 50 line and then glance down holding the vial at your waist level, just a quick glance, don't stare. If you see the dot, then, from the side again (not continuing to look down) fill to 60 line and repeat, etc. Most say doing this outdoors, back to the sun is best, though I'm one of the rare ones I guess that gets more accurate results indoors (this is where that standard solution is very helpful).

So, I'd guess a combination of lag times after addition, some user testing error (we've all done it, no shame!) on top of the inherent error range of any of these tests to explain the unexpected cya results. Just keep monitoring it is about all you can do, but I wouldn't get too hung up on it at this point.

Otherwise, you seem to have a good handle on the TFP principles and are doing the right things. Given that you've been so diligent with staying above minimum, my best guess is that some small amount of algae survived the last SLAM. Usually it is hiding behind light niche, in the ladder, foam of the wier door, something like that. Be sure and check any little hiding spot and brush it.

Did you see this thread of mine? My water was still TFP clear, but I wonder if I would've passed an OCLT.

Hotel Algae

No problem here, just a lesson, or maybe more of a PSA. :) Was on vacation for 8 days and came back to still TFP clear water and FC still above target. I raised to SLAM before I left for insurance in case the SWCG or pump went out from loss of power or whatever - we had a lot of storms...

www.troublefreepool.com

 

[treyrich]

Did you see this thread of mine? My water was still TFP clear, but I wonder if I would've passed an OCLT.

Yeah, I did see this. Crazy! It would have been interesting to see if you would have passed an OCLT on that.

Yeah, like I said, I definitely am not above admitting that I may be botching the CYA test over and over again haha, but I ordered the standard solution so hopefully that can at least add a little clarity to my testing. But it does seem odd that each time I add CYA is when the FC drops out.

I can see what you mean about the potential algae surviving the last SLAM...truth be told I've never seen any visible algae anywhere in the pool at all, the only thing prompting the SLAM has been excessive chlorine consumption and just the slightest cloudiness. I removed every drain cover last time (which was brutal by the way because we have in-floor returns as well so we have 7 drain covers and they're the ones with plaster poured into them and they're super tough to get off haha) and they were all insanely clean. All of my lights are the nicheless style LEDs. My umbrella sleeve has been scrubbed out. My autofill is scrubbed and clean and I pour bleach in it frequently because it scares me that something could potentially grow in there (is this a realistic fear if it gets no sunlight?). The skimmer/weir is freshly scrubbed and never has had any visible algae anyways. I inspected and cleaned both sides of the auto-cover. The only thing that I haven't taken out are the speakers, so I guess I need to get those out.

I will check the speakers this evening, I *think* that's the only spot that there even could be algae hiding.

 

[Pauls234]

You've got all the usual suspects covered and the smart stir so that really helps with FC testing consistency.

Make sure your testing cylinder is clean, you can pour rubbing alcohol or bleach in there and soak it for a bit. We've seen occasions where some residual something in the cylinder consumes FC and skews the test. Also make sure you are testing fairly quickly (within a few minutes) of pulling the sample.

These are less common scenarios, but just trying to rule things out since there is nothing obvious you are missing.

Based on last few logs FC does seem to be holding pretty well with roughly a 2.5 loss over 9 hours of daylight (or maybe mostly daylight?). That's pretty encouraging.

 

[treyrich]

Well, that test is probably somewhat deceiving because I didn't turn off my SWG. I was going to shut it down tomorrow when I can dose the pool more often, but I just figured it would help hold me closer to SLAM levels when I couldn't dose it as often. So you probably have to subtract another ~2 from that number to account for the chlorine added by the SWG.

With that said, that was how the last SLAM went as well, high consumption went away really quickly, but it took days longer to pass the OCLT.

 

[treyrich]

Alright, I could only test twice today, but it seems like the SWG pretty much kept up with things over the day.

Started the day at 6:00 AM with 21.5 FC and added 70oz bleach, then ended the day at 10:00 PM with 21.5 FC and again added 70oz bleach. So the pool consumed roughly 5 FC when factoring in the ~2.2 that theoretically were added by the SWG.

The cover was on 90% of the day, but I do think my wife and kids swam for an hour or two. So not much UV exposure.

It’s hard to tell how clear the water is, it’s definitely clear, but with it being dark it’s tough to see the light cloudiness that may still be present. I’ve never had even a remote difficulty seeing the 8.5’ deep end though.

 

[Pauls234]

I have an above ground pool so not familiar with covers but do they touch the water? Could algae survive somewhere in there?

Consumption of 5 in a day is within normal FC loss range especially at peak of summer, cover on will decrease that some and bathers will increase that and you had both, so.... hard to say definitively other than seems reasonable. FC loss to UV is on a % basis so will be higher in an absolute sense at higher FC levels, though your UV exposure is limited.

You aren't testing CC which is typically not needed in the midst of SLAM, but UV, while consuming chlorine also helps with breakdown of CC. Test CC today just to see if anything going on there.

How clear is the water? Can you post a pic? Is it TFP Clear?

 

[treyrich]

Last night I only lost a net of 0.5 FC, so with the SWG running at 30% that means a total loss of ~1.5. Tonight I will run a proper OCLT. But even if I pass that, I’m still terrified to stop the SLAM because obviously last time I stopped it wasn’t the right time yet.

Yes, covers touch the water, I cleaned both sides of mine a couple weeks ago but it was super clean on the underside though. As I mentioned, I’ve still not ever come across visible algae anywhere in the pool in all of this time.

Yes, as of this morning it is TFP clear, here’s a photo. The cleaner is in 8.5’ of water in the deep end in this photo and I’m standing by the shallow end, overall I’d say we’re looking through ~18’ of water here, it’s overcast so lighting isn’t great, but water doesn’t get clearer than this, other than ripples it’s like there’s nothing there at all.

 

[treyrich]

Forgot to mention, I did the CC test this morning, it was 0.5

 

[treyrich]

FC held pretty solid today. Turning off the SWG now for a true OCLT tonight. Just added some bleach, will test again in a few hours for the night time read, then again in the AM