[sphelps]

I think the slower return rate is related more to effective surface skimming than skimmer contact time. I don't believe for a second the theories relating to matching skimmer flow rates with return rates as they completely independent. However a slower return rate can mean a thinner film being removed from the top water of the display which in theory would hold a more concentrated amount of lighter organics however there are many other variables at play.

Another really important factor to consider is sump design. Skimmer chambers should be designed to trap lighter organics with a baffle and be sized properly for the flow rate of the sump. Ideally organics should float in this chamber just like they would in your display and become trapped with the only exit into the skimmer. I've seen many sumps where water exits the skimmer chamber over a baffle instead of under for example, this setup would probably benefit from the slowest possible flow rate.

At least that's how I look at it.