We don't have a grotto, but we do have a small prayer chapel in our home. I inherited this altar from a dear friend, a retired Byzantine priest. He said Divine Liturgy daily on this altar in his spare bedroom after he retired:
Oh, that is beautiful Dr. Kopp. Thank you for posting the photograph. All that’s missing is The Eucharistic Lord.:):) My husband once asked his brother (the priest!) if we could have Adoration at our home, and he said we couldn’t, but, of course, nothing wrong with a prayer chapel. I’m inspired!