Green Algae with plenty of chlorine present

[tomzo]

Greetings,

When my pool warms up in the summer I get small amounts of green algae forming, primarily in areas where the Kreepy Krauly can't reach (corners, steps, etc). I have a saltwater pool and there is plenty of chlorine always available but I find myself brushing back algae more often than I would like (2x per week). The water is crystal clear and there is not a LOT of algae, but I am wondering how it grows in the presence of chlorine.

Note that this has only begun now that my pool temp is consistently above 80 degrees this summer. It had never shown up in colder temps.

Perhaps this is normal and it is easy to brush off the vinyl surface, but I am wondering if I am doing something wrong.

Thanks

Tom

 

[UnderWaterVanya]

Do you have a test kit? How do you define "plenty"? What are your test numbers?

 

[tomzo]

Never below 3, normally about 5

 

[Stuamurr]

We need a full set of results, including CYA, but 3-5ppm FC may not be sufficient depending on your CYA level to keep algae at bay, if you can do a full test (FC, CC, TA, CH, pH, CYA) those figures will greatly help in anyone assisting you.

 

[tomzo]

Got it - I will get those numbers together and re-post

 

[chem geek]

Since you refer to corners and steps where the algae grows, that sounds like poor circulation. That allows the local chlorine level to get depleted. You might consider orienting your returns differently to try and get better circulation.

 

[tomzo]

Turns out it was low CYA - added some and things have stabilized.

Thanks

 

[jblizzle]

That does not really make any sense.

If there was no CYA and you maintained 3+ppm of FC, there is NO WAY algae would have grown.

Granted that with a SWG you want the CYA to be a little higher to protect the FC from the sun. But, if the CYA was too low, you would have measured 0 FC because it would have been lost to the sun as fast as the SWG could generate it.

 

[tomzo]

The chlorine was getting lost to the sun as it was being generated - there was very low chlorine - lower than I had reported. The pH was a tad high too, but the CYA level was the main culprit.

 

[jblizzle]

there was very low chlorine - lower than I had reported.

Ah, well there is the missing piece of information. Just wanted to be clear for any future browsers of the forum.