CYA level dropping too fast and SWG not keeping up.

[ckendalls]

For a while now it seems like my CYA levels are dropping faster than expected, much faster than my salt levels drop (percentage) due to rain over flow. While out of town for 10 days the CYA dropped from 60 to 30 ppm while the salt level only dropped from 3400 to 3100. This CYA instability seemed to be happening even before we started getting regular heavier rains and the hotter weather with warmer water (currently 88 in afternoon). My almost 4 yr old SWG has also had more trouble keeping up as a consequence although I suspect its also less active than it used to be as I have also had to increase settings to keep up. I had the SWG tested and it passed … but I recently had to commence a SLAM and supplement liquid chlorine when I came back from out of town after a week because likely because the FC levels got too low at settings that had always worked previously to maintain well.

I have read here that there is a bacteria that can eat CYA, but over the few years I have gradually increased my targeted minimum FC which it seems would take care of that (mustard algae levels) as well. Every year it seems that maintaining this pool ecosystem to prevent some infection causing FC depletion gets harder and harder and less forgiving. I had never seen visible growth and the water has always sparkled until a bit of cloudiness recently finally clearing up with SLAMing. I used to be able to set my SWG between 10-20% for less than 8 hrs a day to maintain. Those settings have gone up and up and for longer to maintain and CYA levels drop too fast.

Any thoughts on what is going on here? Why CYA levels are hard to maintain?

BTW, we also have sun sails over the pool to reduce sun inside a screened enclosure for shade.

 

[setsailsoon]

ck,

Yep your swg is right at that point where it starts to lose some of the capacity and that little hiatus down to 2.5 FC probably did you in but looks like you did everything right - lowered pH then started the SLAM. There are several bacteria in the genus pseudomonas that are known to metabolize cyanide compounds. But it's extremely unlikely this is happening in an open chlorinated pool especially at the FC levels in your logs last few months. Could more likely be sun and heavy losses from rain. What test kit are you using for FC and CYA. Looking back at your logs for the past 4 months I don't see where you are getting CYA high enough for our brutal sunny Florida summer. I ran mine 60-70 all summer long here in S Florida with great success. As soon as you get done with the SLAM (not before!) raise your CYA up to 70. I think you'll find this stabilizes the FC.

I hope this is helpful.

Chris

 

[duraleigh]

+1 what setsailsoon said (alliteration to the MAX!)

 

[ckendalls]

ck,

Yep your swg is right at that point where it starts to lose some of the capacity and that little hiatus down to 2.5 FC probably did you in but looks like you did everything right - lowered pH then started the SLAM. There are several bacteria in the genus pseudomonas that are known to metabolize cyanide compounds. But it's extremely unlikely this is happening in an open chlorinated pool especially at the FC levels in your logs last few months. Could more likely be sun and heavy losses from rain. What test kit are you using for FC and CYA. Looking back at your logs for the past 4 months I don't see where you are getting CYA high enough for our brutal sunny Florida summer. I ran mine 60-70 all summer long here in S Florida with great success. As soon as you get done with the SLAM (not before!) raise your CYA up to 70. I think you'll find this stabilizes the FC.

I hope this is helpful.

Chris

Thanks much Chris and thanks for digging in on the logs (admittedly a bit incomplete at times). I use a 2006C Taylor test kit.

As I mentioned it has been difficult to get the CYA up and holding. The CYA levels seem to drop at a rate much faster than the Salt level which leads me to believe it is not washout from rains. Is CYA that sensitive to heat? Its as if I’d have to add 1-2 lbs a week to sustain my CYA levels… I have usually targeted 50-60 since we are screened in and have sun sails for shade, but will try to get up to 70 once I see that things are really in hand. I also doubt its Pseudomonas bacterial. (BTW, FWIW …. I lead the effort that sequenced the 1st Pseudomonas aeruginosa genome over 20 yrs ago. Hopefully this isn't revenge ).

The pool may be recovering as it passed OCT this morning. I have never scene actual visual evidence of mustard algae except the symptomatic toughness of whatever I have gotten in the last year or two periodically suggest something of that ilk. The “pool fever” never seems to break at normal SLAM levels until I get up to mustard shock levels.

Thanks again, Ken

 

[ckendalls]

Why not use tabs instead of liquid chlorine? The only reason to use liquid chlorine is to avoid running up your CYA.

I have an SWG. So unless I need to SLAM I dont have to supplement. But if I have trouble keeping up my stabilizer, especially when out of town, maybe tabs are worth considering since they also have CYA. Thanks.