Something to keep an eye out for …

[Katodude]

I’m telling you my pool must be full of those enzymes. CYA dropped from 80 to 60 in the last two weeks. No rain to speak of, and no splash out since still too cold for the pool.

 

[fishbait]

I’m telling you my pool must be full of those enzymes. CYA dropped from 80 to 60 in the last two weeks. No rain to speak of, and no splash out since still too cold for the pool.

I believe I have a CYA eater as well. Went from 120+ to around 70 over winter, I was measuring to figure out how much water to drain and replace at opening this year. Couple weeks later was down to 50. Two weeks or so later (Last night) It was down to 40! I just now got back from WM with some clorox CYA to bring it up to 70 before I install my new RJ60. I'm glad I don't have to drain and replace, but also confused since that is supposed to be the only way to lower it!

 

[AUSpool]

I believe I have a CYA eater as well. Went from 120+ to around 70 over winter, I was measuring to figure out how much water to drain and replace at opening this year. Couple weeks later was down to 50. Two weeks or so later (Last night) It was down to 40! I just now got back from WM with some clorox CYA to bring it up to 70 before I install my new RJ60. I'm glad I don't have to drain and replace, but also confused since that is supposed to be the only way to lower it!

Reduction of CYA over winter is a reoccurring theme, particularly in covered winterised pools. Most likely a anaerobic bacteria using the CYA as a food source. There is some supporting literature based on how sewage treatment plants remove CYA in anaerobic digesters. Slow degradation in the order of 5-10ppm per month over summer will also occur due to heat, UV and FC.

 

[Mdragger88]

Reduction of CYA over winter is a reoccurring theme, particularly in covered winterised pools. Most likely a anaerobic bacteria using the CYA as a food source. There is some supporting literature based on how sewage treatment plants remove CYA in anaerobic digesters. Slow degradation in the order of 5-10ppm per month over summer will also occur due to heat, UV and FC.

There’s a piece of this puzzle that I haven’t tracked but I am curious to know & will be watching for. How many of those pools that lose substantial amounts of cya over the winter close @/near SLAM level for their cya?
I always do & my cya is always almost the same as it was when I closed (maybe 5-10ppm less)
I also usually open with 10+ fc level remaining which I have to assume wards off this bacteria
I use a solid cover & close/open with water in the low 60 degree range.

 

[ajw22]

I also usually open with 10+ fc level remaining which I have to assume wards off this bacteria

None of that matters. It is dependent on peoples local environment and the eco system the pool lives in.

There is not CYA eating bacteria everywhere that you can ward off by doing certain things.

I think it is connected with fertilizers and farming chemicals. Ammonias are used in farming and are known to eat CYA. Water runoff can carry it into pools.

 

[fishbait]

There’s a piece of this puzzle that I haven’t tracked but I am curious to know & will be watching for. How many of those pools that lose substantial amounts of cya over the winter close @/near SLAM level for their cya?
I always do & my cya is always almost the same as it was when I closed (maybe 5-10ppm less)
I also usually open with 10+ fc level remaining which I have to assume wards off this bacteria
I use a solid cover & close/open with water in the low 60 degree range.

I simply covered my pool, peel back cover and check.levels and adjust as normal every week or 2. Wasn't measuring CYA because it was 120+. So my FC was being added based on 120, so could have been higher than required if CYA dropped below 120 and I didn't know.

 

[Saturn94]

There’s a piece of this puzzle that I haven’t tracked but I am curious to know & will be watching for. How many of those pools that lose substantial amounts of cya over the winter close @/near SLAM level for their cya?
I always do & my cya is always almost the same as it was when I closed (maybe 5-10ppm less)
I also usually open with 10+ fc level remaining which I have to assume wards off this bacteria
I use a solid cover & close/open with water in the low 60 degree range.

I close at SLAM level and always lose a lot of CYA (sometimes all!) over the winter. For reference, CYA at closing is usually about 70ppm.

 

[magiteck]

There’s a piece of this puzzle that I haven’t tracked but I am curious to know & will be watching for. How many of those pools that lose substantial amounts of cya over the winter close @/near SLAM level for their cya?
I always do & my cya is always almost the same as it was when I closed (maybe 5-10ppm less)
I also usually open with 10+ fc level remaining which I have to assume wards off this bacteria
I use a solid cover & close/open with water in the low 60 degree range.

I close at SLAM level and always lose a lot of CYA (sometimes all!) over the winter. For reference, CYA at closing is usually about 70ppm.

This spring, I opened to the same (it actually measured a bit higher?) cya level that I closed at.

Last spring, i had an undetectable amount of CYA in the water.

I give up on trying to understand the logic.

 

[Saturn94]

…I give up on trying to understand the logic.

You and me both!

 

[Mdragger88]

I will just keep counting myself lucky & keep doing what I’m doing.

 

[AUSpool]

This all demonstrates the practical application of bacterial enzyme augmented degradation of cyanuric acid in a low nutrient and close to sterile environment by untrained users - it’s going to be harder to control and predict the outcome then control a flock of seagulls at a chip eating contest.

We’ve seen these products come and go before, the process is promising in the lab but actual real application falls short. We might even hear of positive results but there is no way of directly linking a reduction in CYA to the use of these products when the application process favours the reduction of CYA from wild bacteria. We also know that CYA testing is subjective with a high variance which can also lead to a false positive.

 

[Mdragger88]

it’s going to be harder to control and predict the outcome then control a flock of seagulls at a chip eating contest.

This is golden

 

[Newdude]

This is golden

It works for his chips and ours. Dump ducks are not picky. At. All.

 

[AUSpool]

There’s a piece of this puzzle that I haven’t tracked but I am curious to know & will be watching for. How many of those pools that lose substantial amounts of cya over the winter close @/near SLAM level for their cya?
I always do & my cya is always almost the same as it was when I closed (maybe 5-10ppm less)
I also usually open with 10+ fc level remaining which I have to assume wards off this bacteria
I use a solid cover & close/open with water in the low 60 degree range.

Closing and opening at or near SLAM level would be only one of many factors to consider. There are a bunch of factors that we know of but due to the length of time over winter there could also be a bunch of factors we just haven’t thought of. Its called confounded in time.

I agree, opening at, and/or maintaining ideal FC levels over winter would ward off bacteria just as it would over summer. I also think that there’s more to it then just FC levels though, low to no oxygen would also be required which is what the cover does. It’s almost certainly bacterial related which means a starter culture is required and environmental conditions for a culture to thrive but since the process is confounded in time it may be something else. The fact that all the reports of CYA loss come from closing over winter seam to imply cold weather and plenty of time is required but it could just be that this is the only time that lots of people through a tarp over their pool. The entire process may occur in the last week or two when the water has warmed up.

It would be nice to tell someone whose battling with high CYA and is right on the edge of a full blown algae outbreak just to through a tarp over the pool and turn everything off for two weeks and then start over. But unfortunately that same person would be in denial that half their water needs replacing with fresh and easily lured by a LPS’s offer of a quick fix from a bottle.

 

[IceShadow]

There’s a piece of this puzzle that I haven’t tracked but I am curious to know & will be watching for. How many of those pools that lose substantial amounts of cya over the winter close @/near SLAM level for their cya?
I always do & my cya is always almost the same as it was when I closed (maybe 5-10ppm less)
I also usually open with 10+ fc level remaining which I have to assume wards off this bacteria
I use a solid cover & close/open with water in the low 60 degree range.

We close with slam-level FC and polyquat 60, but we have a mesh cover and by the time we open FC is 0. CYA is typically 0 or close to it as well. I typically add 30ppm worth in case it's got 10 or 20 (and my gauge doesn't go below 30).

 

[blazer58]

We close with slam-level FC and polyquat 60, but we have a mesh cover and by the time we open FC is 0. CYA is typically 0 or close to it as well. I typically add 30ppm worth in case it's got 10 or 20 (and my gauge doesn't go below 30).

Same here and every opening 0 cya
This year I will be using pucks and some cya via sock method till I can run my swg
Have not tested opened this year but we had way less snow then years past
Curious if that makes a difference
(Cya at closing is 70/80)

 

[Mdragger88]

I closed oct 20th w/ cya of 70 fc 28 & opened April 5th w/cya of 60 & fc 15.5
No polyquat.

 

[borjis]

I lose at least 20ppm some times more every winter. Pool is uncovered. Previous owners used a tab feeder I promptly removed after buying the place.