Interesting. I too was advised to run the pump basically for as long as the sun was on the water. That's about 9 hours in summer and 6 in winter. Since I read the article, I have been running my pump 2 1/2 hours and the water looks great. It will be interesting when it warms up to see what happens. Right now there is no bather load. (Water is 68 degrees)

Mark points out that longer run times may be needed for SWCG systems. I suppose the same is true for solar heat at times. During times when you want to get the most heat into your pool, you will want to run the pump for as long as you get a temperature differential (of some minimal amount).