"Hymn No. 73 (Holy, Holy, Holy): This hymn was originally written in 1826 by Reginald Heber.
In its original form it was a Trinitarian song, which read at the end of the first and fourth stanzas follows: “God in three persons, blessed Trinity!”
This song was placed in the 1909 and 1941 Seventh-day Adventist Hymnals, but the trinity part was at that time changed to: “God over all who rules eternity!” and “Perfect in power, in love and purity.”This song was purposely changed into a non-trinitarian song by Seventh-day Adventists, expressing their views on the Trinity back then.
In the new 1985 Adventist Hymnal this song was changed back to its Catholic original, praising a three-in-one God. But this is not Scriptural."
From http://thegreatcontroversy.info/errors-in-the-new-sda-hymna.html