SB 3.20.15
so ’sayistabdhi-salile
andakoso niratmakah
sagram vai varsa-sahasram
anvavatsit tam isvarah
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
For over one thousand years the shiny egg lay on the waters of the Causal Ocean in the lifeless state. Then the Lord entered it as Garbhodakasayi Visnu.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
From this verse it appears that all the universes are floating in the Causal Ocean.