Daddy builds a Beckett while baby is sleeping:)

[Canadian Man]

Your correct Doug. The water height is just below the first flange.

The reason for the long 1.5" pvc pipe;
1. Forces the air/water mixture deep into the tube of the skimmer, increasing contact time.
2. Eliminates bubbles exiting the skimmer. There is basically 0 bubbles exiting the skimmer.
3. The center tube design helps eliminate the burping that skimmers using the bottom as a mixing box tend to suffer from.