Jamieson, Fausset and Brown on Jeremiah 52:20

20. bulls ... under the bases--But the bulls were not "under the bases," but under the sea (1Ki 7:25, 27, 38); the ten bases were not under the sea, but under the ten lavers. In English Version, "bases," therefore, must mean the lower parts of the sea under which the bulls were. Rather, translate, "the bulls were in the place of (that is, 'by way of'; so the Hebrew, 1Sa 14:9), bases," or supports to the sea [Buxtorf]. So the Septuagint. 2Ki 25:16 omits the "bulls," and has "and the bases"; so Grotius here reads "the bulls (which were) under (the sea) and the bases."