Assuming the same number of turnovers per day, if you have your pump running for a longer period of time (at lower GPM) so there is less "idle" time in the water, then technically that is better since it ensures the best continual mixing of the water and even distribution of chemicals. It helps prevent a local area from getting depleted in chlorine due to localized consumption.
Now that said, there are points of diminishing returns so in practice anything more than 8 hours of pumping per day might not be much of an issue, especially if that 8 hours is during the sunny part of the day where a localized drop in chlorine would be more likely if the sun hit only a part of the pool and you measured FC taking water from the shady part of the pool.
So from a practical point of view, when I get my IntelliFlow pump, I plan to have it run as slow as possible until I reach a point where it starts becoming inefficient (in terms of daily electrical usage). This might be quite a bit less than 24 hours -- I'll have to see when I get the pump. In practice, during the day, the solar will be on part of the time and will be pumping at a much higher GPM rate such that I'll achieve a full turnover long before even 8 hours, at least when the pool needs to "catch up" in temperature.
Richard
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