Is this the beginning of
Bryopsis?
*****
It's a new tank (30g total), but stocked with fully cured LR (~30-35lbs) and several cups of LS (to go with the new southdown). Lots of tiny pods on the glass. In the 10g sump, there is a small fuge area with LR rubble, LS and big clumps of chaeto. I have a SeaClone that I just started up that isn't doing much yet. So I have some degree of nutrient export, and I'm changing 4g every week. It's been ammonia free for two weeks now, and its first inhabitant (except for snails and hermits) is a cleaner shrimp that appears to be doing well.
Also, as far as size is concerned, those are grains of southdown at the base of the algae in the pic...