Proper substrate for Osp. Brazilian Sun 'Samba'

[awharvey]

My wife and I recently had our 28th anniversary, which we learned was our "orchid" anniversary! So to celebrate we got ourselves a beautiful Osp. Brazilian Sun 'Samba' from Palmer Orchids. It arrived in a 3" pot with two gorgeous spikes in bloom. The plant tightly fills the pot, but you can tell the substrate is entirely sphagnum. Is a proportionately small pot with only sphagnum a good idea for this type of orchid? It definitely holds water much longer than our other pots, which are proportionately larger and use a more typical orchid bark/charcoal/sphagnum mix.