Skimming, Is It All Just A Load Of Old Froth?

[Fingers68]

Deltec 300 skimmer.

I have been tweaking with this for a month now. Just getting the right setting with the air tap to give the most froth without pumping loads of bubbles into my tank. I think I have found the "sweet spot" with the air tap, but I can not be sure. Then there is the cup height?

If I am to adjust the cup height to vary the amount of liquid collected in the cup, just how much per day should be skimmed off to get the best out of it?

Given the same period,

Little volume that is very dark and smelly with dark scum around the top of the cup.
or
More volume that is much lighter in colour with a little scum around the top of the cup.

Is there a difference? are both cleaning the same amount of water just the first one is recycling more efficiently.

 

[SkiFletch]

It used to be generally accepted among hobbiests that wet skimming (ie high-volume, lighter color) was more effective. A recent quantative study posted in advanced aquarist online magazine however debunks this practice, instead proving that either skimming method (wet or dry) is equally effective at removing nasties from the water column. Don't have the direct link handy, but it was a very recent article on the online mag, within a couple months or so.