What is the best HOCL (as ppm CL2) number to aim for

It might be that the winds whip up a higher "Organic Load".

I found this article interesting; any thoughts?

http://www.water.siemens.com/SiteCol...20Chlorine.pdf

Many times people think they have yellow/mustard algae when they really have pollen. The main difference between the two is that the yellow/mustard algae will tend to stay on the shady side of the pool while the pollen will settle wherever circulation takes it and usually right on the bottom. Yes, pollen will create an extra organic load and therefore a chlorine demand. A skimmer sock is often the best way to remove the pollen as it tends to stay on the surface for a while so can get into the skimmer before it gets water logged and drops.

If you are able to get a sample of these yellow spots (carefully taking a turkey baster or something like that to suck some up), then if you look under a microscope you can tell the difference more readily. Pollen is round or spiky and solid-looking. Algae is more translucent and usually oblong.

You may be correct that you have pollen instead of yellow/mustard algae. That is usually the case. However, higher chlorine levels won't keep away pollen, but it will tend to break it down faster.

Richard

chem geek,

You are correct it is pollen, so now I keep the cover on and that seems to reduce the problem; taking it off for 2 hours a day to vent the pool.

Thank you for your help.