The Mystery Pool

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Seadweller

Well-known member
Aug 21, 2009
230
Tampa Bay Area
Well, somehow, with every pool I've owned, I end up with the "Mystery Pool." I fought algae in our current pool for several years, when I finally converted to the "TFP Method" which helped but didn't completely eliminate my troubles. Around 4 or 5 months ago, I finally converted to a salt system. The salt conversion was the best thing I've ever done, and I wish I had done it years ago.

Anyway, I'm mystified by the fact that I had green algae this morning, in the deep end, on a wall that is 90% in the shade. My test results as I expected are nearly perfect, as I've been testing continually with the TFP test kit and Taylor mixing device.

FC - 9
CC - 0
pH - 7.6
CYA - 80
Alch - 120
Salt - 3,600

The pH leveled off at 7.6 about 3 weeks after converting to the salt system and has remained there, and FC has never dropped below 7 (which is high according to the CircuPool manuals 1ppm-3ppm). According to the control unit, the salt level has remained between 3,400 and 3,600 since I installed it, which I verified with test strips. There has been no bather load, and very little debris in the pool. I even increased the pump RPM's to provide better water circulation. I'm running the pump around 8 hours per day, starting at a higher RPM for 2 hours, then a lower RPM for 6 hours. The CircuPool unit is running for 6 hours at 50% currently.

What all of that said, how the heck can algae be forming? I can't imagine an FC that's too high would cause the issue. The water is warmer, but obviously nowhere near summer temperatures. What kind of algae issues am I going to have in the summer, and why?

Should I start dosing the pool regularly with an algaecide?

Any input/advice would be most appreciated.
 
Odd - but a couple items based on your discussion.
Be sure to follow the [FC/CYA][/FC/CYA]. You stated a 1-3ppm range - NO.
How do you test? If you have your own test kit put that in your signature. If not, get your own test kit. It is best to use your test kit and do the tests just before the SWCG is set to start for the day. That way you are seeing the FC at its lowest point of the day.

Brushing? Robot? You still need to brush or have a robot that brushes. Algae can form in 'dead' water areas and brushing disturbs that.

Take care.
 
Sead,

I just don't think you ever got rid of the initial algae...

I suggest that you perform a SLAM.. See this SLAM Process

And make sure that you pass all three criteria before stopping the SLAM..

You might also look behind the light and under any ladders...

Thanks for posting,

Jim R.
 
Thanks gentlemen...To a few of your points:

1. I do test in the AM before the salt system fires up for the day. Since installing it, the FC has never dropped below 7, and has typically remained at a 9 or 10.
2. I have the full TFP test kit with the Taylor stirring device.
3. I do have a "The Pool Cleaner" running in the pool, but only every 3-4 days when a few leaves and such find their way to the bottom.
4. Brushing is something I'm not religious about. Perhaps that could be the issue?
5. There's nowhere for algae to hide in the pool, except behind the pool light. Oddly enough, the pool has was clear for a week before this "bloom" appeared on the wall this morning. Is it coincidence that this "bloom" was near the pool light?

Is it necessary to perform a "SLAM" when CC's are at zero?

Thanks!
 
Sead,

If you have visible algae, then a SLAM is our recommended fix...

If you wish, you can try an OCLT first, but I don't see the point. See this ... Overnight Chlorine Loss Test

Under normal conditions, I believe that robots can take the place of brushing... But, once you have visible algae, you need to brush more often, and by hand.. this breaks up the top layer of algae so that chlorine can get inside and kill it...

Thanks,

Jim R.
 
Brushing is absolutely necessary as algae will develop a "biofilm" protective covering that shields it from the chlorine. If you don't brush and disrupt this biofilm you aren't getting chlorine to the algae.

Look behind that light! It may be a virtural swamp back there and you'll never know unless you take it out and look. We've seen pictures that would curl your toes of such swamps!!

Maddie :flower:
 
OK, when the water temps come up a bit, I'll pull the pool light to see what might be back there. I don't think I fit in my spring suit anymore. :D

Will a SLAM routine take care of what's behind the light, or does that have to be removed regardless?

Thanks!
 
Seadweller said:
Well, somehow, with every pool I've owned, I end up with the "Mystery Pool." I fought algae in our current pool for several years, when I finally converted to the "TFP Method" which helped but didn't completely eliminate my troubles. Around 4 or 5 months ago, I finally converted to a salt system. The salt conversion was the best thing I've ever done, and I wish I had done it years ago.

Anyway, I'm mystified by the fact that I had green algae this morning, in the deep end, on a wall that is 90% in the shade. My test results as I expected are nearly perfect, as I've been testing continually with the TFP test kit and Taylor mixing device.

FC - 9
CC - 0
pH - 7.6
CYA - 80
Alch - 120
Salt - 3,600

The pH leveled off at 7.6 about 3 weeks after converting to the salt system and has remained there, and FC has never dropped below 7 (which is high according to the CircuPool manuals 1ppm-3ppm). According to the control unit, the salt level has remained between 3,400 and 3,600 since I installed it, which I verified with test strips. There has been no bather load, and very little debris in the pool. I even increased the pump RPM's to provide better water circulation. I'm running the pump around 8 hours per day, starting at a higher RPM for 2 hours, then a lower RPM for 6 hours. The CircuPool unit is running for 6 hours at 50% currently.

What all of that said, how the heck can algae be forming? I can't imagine an FC that's too high would cause the issue. The water is warmer, but obviously nowhere near summer temperatures. What kind of algae issues am I going to have in the summer, and why?

Should I start dosing the pool regularly with an algaecide?

Any input/advice would be most appreciated.
Click to expand...
What is "Alch"? Is that your TA or CH?

If you add your test kit to your signature we will stop asking which test kit you have :wink:
 

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