I think it’s proportional as a % of FC at a given CYA level. Is this right? (just futzing around with dialing in the SWG for my pool and my sun exposure — trying to make trend predictions and testing the outcome)
Need some basic advice -TA, pH, CH, FC all things chemical
- Thread starter SoDel
- Start date
- May 11, 2021
- 973
- Pool Size
- 7000
- Surface
- Vinyl
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-30
Yes. The higher the FC for your CYA level the higher the chlorine loss. Not a constant, but not linear either (so not a %). The are several old discussing on The Deep End about the subject.
The ladder rails were not emptied/flushed per procedure with the first SLAM and the lights were not inspected either. Neither of those garauntee a recurring bloom but certainly open a wide door to the possibility. There could always be another overlooked spot reducing the success of the process.
We can only do so much from afar and rely on the OP doing their part of it. We can only suggest so many possibilities for them to check. It's not the processes fault if something is overlooked, and we may never get the AHA moment if SLAM # 3 cleans it behind the scenes. It is also not the processes fault if the OP strays and tries to blend different processes. For example, using our process with only occasional pool store testing to guide it. It fails for the frequency of testing far more than the accuracy of the testing. (Which it of course also fails)
To speak to your earlier point discussing the science as absolute values of sanitation/ FC protection, that was our start point. We have fine tuned it over the years with thousands and thousands of real world members reporting real world results of said science. You will find the current forum absolutely littered with 'YMMV', 'listen to your pool' 'The ideal ranges are a suggestion to start from'. 'FC is safe all the way to SLAM level, and 'don't sweat being a little over target range'
So don't confuse the science in a lab with how we implement it in the real world, or even how we implemented it years ago before we had more real world data to fine tune it further. Doing so takes either out of context and diminishes them both.
Read the old threads, the science, the implementation of it all, and understand them each in their proper contexts. More often than not, they compliment each other instead of one disproving the other.
Will do.
But the thing about ladder rails and light niches raises more questions about how Cl and algae (assuming “ordinary” algae) interact, pool circulation (and lack thereof), and places with no sunlight. I’ll start a new thread when I have a better idea of what’s nagging in the back of my mind.
It didn't start in those places, It starts in the pool. The infected water makes its way into the low circulation/sunlight areas and then mostly lies dormant. Once it leeches out later, it regains its growth potential. Some SLAM water seeps in there during the process but without the proper circulation of fresh SLAM water, it doesn't fully irradicate the problem. Then the fixture (etc) becomes the future source when it wasn't the original source.
We often skip the lights on the 1st SLAM as it's a pain, and we've already given the OP so many things to do. but it's one if the first things we suggest on a replay. It doesn't harm every SLAM, or even most of them so it's a calculated risk to let it go the first round.
In a perfect world with an OP with unlimited energy and time, we'd pull every stop, everytime.
- May 23, 2015
- 25,709
- Pool Size
- 16000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
UV Loss is dominated mostly by the presence of hypochlorite as it is most sensitive to longer wavelength UV (UV-A and UV-B) from the Sun. Hypochlorous acid is more sensitive to short wavelength UV (UV-C), but vey little of that reaches the Earth's surface thanks to the ozone layer's protective benefits. Sanitizing chlorine is reduced by UV light to chloride ion (Cl-) along with the formation of oxygen gas.
See this old post for details -
www.troublefreepool.com
See this old post for details -
Pool Water Chemistry
This thread presents my findings so far on pool water chemistry including the following: More Accurate Calcite Saturation Index (CSI) to replace Langelier Saturation Index (LSI) Calculation of ppm HOCl (disinfecting chlorine) at various levels of Total Free Chlorine (FC) and Cyanuric Acid (CYA)...
www.troublefreepool.com
Oly
Gold Supporter
The fact, "Life Finds a Way" applies to algae too.
@chem geek, you refer to a paper in this post (from long ago).
www.troublefreepool.com
Link in the post is no longer to an active resource. The title is “Extended experimental investigation: The effect of sunlight on the chlorine levels in pools.” @chem geek, do you have an updated link to it or does anyone? Thanks.
Pool Water Chemistry
Thanks JasonLion. Maybe the page could say "the range should be 7.5 to 7.8 with 7.7-7.8 being ideal". Then someone would need to offer a suitable pH kit of course: cresol red covers the required range. Extensive experience is important, but there is probably very little experience (let alone...
www.troublefreepool.com
Heh, heh, so does agent HOCL find a way. I’d be inclined to keep bumping FC (within reason, which I can’t quite figure yet — I’m still not quite getting why a short term extreme FC excursion is so terrifying but I defer. Too many variables and details and so little time) until all the nooks and crannies get a lethal dose. It is war and desperate times call for desperate measures. Improvise, adapt, overcome.
Green algae needs sunlight to survive. A week, tops in the dark and it’s dead with zero HOCL. Is there sunlight in the lightwells and inside ladders? (Real question, I have neither. For safety I have lights but they’re integrated in the shell; no ladders, just stairs part of the shell).
Also, in many pools there are unavoidable places of stasis. Like the light conduits. There are just going to be dead zones so if the usual process isn’t working, there maybe needs to be a plan B?
Also there are the spores, but the spores are always there. Every strong breeze delivers more.
Doesn’t it just a boil down to kill it faster than it can reproduce, and if it keeps reproducing that means it has to be killed faster? Increase HOCL?
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This is where you are wrong. There are a LOT of times green and black algae have been found behind lights and inside ladders that do not see any daylight. Here is just one example:
Black Algae Behind Pool LIght
I made a big discovery today, behind my pool light there was a very large deposit of black algae. Since last year I have been chasing a chlorine demand/ loss of CYA issue brought on by the premature failure of a new salt cell last year. The pool generally looks very good, clear water, no stains...
www.troublefreepool.com
Light niches have proven to harbor algae indefinitely.
Watch the 2 videos in the first post.
Jumped in head first into the deep end with our first pool, thank God I found TFP! (Things I learned about SLAM and Pool Stores)
Quick background: After purchasing a new home that came with a pool, I knew my knowledge was at a solid zero and that I'd need some major help. We turned to the company that the home's previous owners used to open/close the pool which informed us they no longer serviced our area. So I did some...
www.troublefreepool.com
- May 11, 2021
- 973
- Pool Size
- 7000
- Surface
- Vinyl
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-30
I don’t think Richard is still active….
You might be looking for this:
You might be looking for this:
But black algae is actually a bacteria so I don’ think that’s really what we’ve been talking about. I’m not aware of black algae fouling the water overall. Does it? All I’ve ever seen described is sort of staining surfaces.This is where you are wrong. There are a LOT of times green and black algae have been found behind lights and inside ladders that do not see any daylight. Here is just one example:
Black Algae Behind Pool LIght
I made a big discovery today, behind my pool light there was a very large deposit of black algae. Since last year I have been chasing a chlorine demand/ loss of CYA issue brought on by the premature failure of a new salt cell last year. The pool generally looks very good, clear water, no stains...
That's hard to argue with lol. But I’d still say somehow the algae was getting sunlight. Still, let’s go with immortal green algae that can survive without sunlight (let’s say it goes dormant and revives from time to time, who knows), there are still inaccessible areas of stasis in many pools (I mentioned the lighting wire conduits). Can’t be brushed. What to do?Light niches have proven to harbor algae indefinitely.
Watch the 2 videos in the first post.
Jumped in head first into the deep end with our first pool, thank God I found TFP! (Things I learned about SLAM and Pool Stores)
Quick background: After purchasing a new home that came with a pool, I knew my knowledge was at a solid zero and that I'd need some major help. We turned to the company that the home's previous owners used to open/close the pool which informed us they no longer serviced our area. So I did some...
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That’s ok, if it’s happening, it’s happening and I stand corrected. But what if you can’t get in there or there are other places you can’t get to? There’s got to be a way to destroy that algae or the pool would be a maintenance nightmare.
- Mar 5, 2020
- 3,221
- Pool Size
- 66000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Astral Viron V35
Just thought of another factor, that might add the list of enablers for lower target- and min-FC with SWGs:
Many (most?) SWG-owners would dial their SWG in, so that it creates enough chlorine on high UV days. And then leave it. If the weather turns cloudy for a while, FC will move up. That gets tolerated as long as it stays below SLAM-FC.
Doesn't that mean that SWG-pools get collateral "Mini-SLAMs" from time to time? Maybe not at full SLAM-FC, but probably for a couple of days somewhere between target-FC and SLAM-FC. In a pool that is pretty much algae-free to start with, that should extinguish any potential algae-seeds quite effectively. Liquid chlorine pools don't get that, as TFP-followers would test before adding chlorine, and then add less on a day with less chlorine loss.
That should keep any potential algae-seeds in an SWG-pool on average in check, allowing (together with other factors) lower FC in-between "Mini-SLAMs". Just an idea...
Would be interesting to see if there is a correlation between algae outbreaks in SWG-pools and being too OCD about keeping FC always as low as possible (but still above SWG-min), and constantly re-adjusting the SWG.
Many (most?) SWG-owners would dial their SWG in, so that it creates enough chlorine on high UV days. And then leave it. If the weather turns cloudy for a while, FC will move up. That gets tolerated as long as it stays below SLAM-FC.
Doesn't that mean that SWG-pools get collateral "Mini-SLAMs" from time to time? Maybe not at full SLAM-FC, but probably for a couple of days somewhere between target-FC and SLAM-FC. In a pool that is pretty much algae-free to start with, that should extinguish any potential algae-seeds quite effectively. Liquid chlorine pools don't get that, as TFP-followers would test before adding chlorine, and then add less on a day with less chlorine loss.
That should keep any potential algae-seeds in an SWG-pool on average in check, allowing (together with other factors) lower FC in-between "Mini-SLAMs". Just an idea...
Would be interesting to see if there is a correlation between algae outbreaks in SWG-pools and being too OCD about keeping FC always as low as possible (but still above SWG-min), and constantly re-adjusting the SWG.