new algae problem, any thoughts?

[mbone]

29,000 SWG inground

FC 10
pH 7.5
TA 110
Borates 50ppm
T 72 F
CYA 26, added 7lbs. last week
pump 9 hrs. 4.5h am/ 4.5hpm
Ca++ 310


Getting ready for the season to open here in N.O.,LA. However, I had a recent algae bloom for unknown reasons. My numbers seem fine to me. The only unusal thing to happen was a sudden introduction of fresh water from a storm the other day. The reason I bumped the FC llast week to compensate for the increasing CYA. Any suggestions on the bloom and to get rid of the green?

 

[tagprod]

what was the chlorine and cya levels before the storm? that cya level seems really low for a swg. Maybe you didn't have any chlorine in the pool?

 

[JasonLion]

Welcome to TFP!

I would not expect algae to last for long with FC at 10 and borates of 50. It isn't that hard for some algae to get started right after a storm, but if you keep your FC level steady, which generally means extra chlorine, then you can usually beat it easily. However, if the FC level dropped once the algae got going then it makes a lot more sense. A big storm can overwhelm the chlorine in the pool and once the algae gets going the SWG can't keep up.

In any case the solution is extra chlorine, I suggest using bleach, and a longer pump run time. I would bring the FC level up to 15 and make sure it stays there by checking and adding extra chlorine at least twice a day and run the pump 24/7 for a couple of days and that should clear it up.

 

[mbone]

Tagprod,

The CYA was probably around 55? (26 plus the 7lbs I added). The FC was 4.5 before the storm.

 

[duraleigh]

mbone,

Did you bump your FC to 15 with liquid chlorine per Jason's suggestion? Relying on an SWG for algae removal is frequently not very effective. A big dose of chlorine is normally the fix.

How does your water look?

 

[tagprod]

Tagprod,

The CYA was probably around 55? (26 plus the 7lbs I added). The FC was 4.5 before the storm.

Let me make sure I got this all straight - your CYA before the storm was 26 and FC was 0(?) then after the storm you added CYA and chlorine to up your levels - is that accurate?

 

[mbone]

Off to Sam's to get bleach. I was concerned about running the pool at high CYA(80) as I always ran it in the 30 range. As I continue to read, it seems that my SWG pool will be more efficient with ^CYA.