Thanks, y'all! What I've found is that the juveniles compete very poorly vs. algae of pretty much any kind. In fact, the parent colony of the polyps above very nearly lost a battle with Valonia (evil stuff) itself. The juveniles that I have that are doing well are all in shaded places (the one above is on a rock overhang) that get really good water flow (the overhang juts out into the current a bit right in a place where return water has banged into the glass and is taking the water down and around the rock). It's really in a perfect place to sieve food particles from the water and it doesn't have to fight the algae.
I was thinking that I might try setting up a darkened raceway with brood stock near the water inlet to give tons of surface area for larvae to settle that all gets really good flow. Maybe set up a constant drip of food at the broodstock end and have the whole thing drain to feed a large display tank.
Oh, the larvae seem to prefer to settle on plastic rather than glass (PVC, the plastic of an internal overflow, the outside cases of powerheads). So, I want to build the raceway of darkened acrylic.
And that's my report....
