In 1855 Manns was invited to conduct a summer season of concerts in Amsterdam, after which he returned to England to take over at the Crystal Palace when the management, led by George Grove, secretary of the Crystal Palace Company, (later famous as the editor of the Grove Dictionary of Music and Musicians), dismissed Schallehn for his unsatisfactory work.
The Musical World wrote, 
The change will, we trust, lead to some necessary improvements in the band.
Herr Manns has a capital opportunity of distinguishing himself.
His resources are sufficient to constitute one of the finest bands in the kingdom, and we shall be glad to find the Crystal Palace orchestra achieve such a reputation under his conductorship. ...
Herr Manns is too intelligent a musician not to appreciate the nature of his resources and the requirements of his public.
It may be safely predicted, that the music at the Crystal Palace will be one of its principal attractions within a short time after the instalment of the new director.

The rest of Manns's career was almost exclusively associated with the Crystal Palace.
When he took over, the permanent band was a wind ensemble, from which, with four specially engaged string players, Manns improvised an orchestra of about thirty-four performers.
With the backing of Grove  and the directors of the Crystal Palace he gradually expanded the band into a full orchestra, for which a new concert room was added to the Crystal Palace.
Together, Grove and Manns made the Crystal Palace concerts the principal source of classical music at popular prices.
The concert season ran from October to April, with concerts given on Saturday afternoons from 1855 to 1901.

Within months of his appointment, Manns gave the first London performance of Schumann's Symphony No.
4 in D minor and the British premiere of Schubert's "Great C major" Symphony.
 His concerts featured the music of more than 300 composers.
There were more Austro-German composers (104) than those of any other nationality, but British composers (82) came a strong second.
Manns was the first conductor to introduce Arthur Sullivan to the English public, when he conducted the young Sullivan's Tempest music in April 1862.
Manns later introduced early works by William Sterndale Bennett, Charles Villiers Stanford, Hubert Parry, Hamish MacCunn, Edward Elgar and Edward German.
Thirty years after Manns introduced the Tempest music, Sullivan wrote to him, "How much do I not owe to you, my dear old friend, for the helping hand you gave me to mount the first step on the ladder!
I shall always think of you with gratitude and affection."
Among contemporary continental composers, Johannes Brahms (in 1863), Joachim Raff (in 1870), and Antonín Dvořák (in 1879) also first became known in England through Manns's Crystal Palace concerts.

Some fragments of a live performance of Handel's Israel in Egypt conducted by Manns at Crystal Palace in 1888 are among the earliest surviving recordings of classical music.
In 1855 Manns was invited to conduct a summer season of concerts in Amsterdam, after which he returned to England to take over at the Crystal Palace when the management, led by George Grove, secretary of the Crystal Palace Company, (later famous as the editor of the Grove Dictionary of Music and Musicians), dismissed Schallehn for his unsatisfactory work. The Musical World wrote, 
The change will, we trust, lead to some necessary improvements in the band. Herr Manns has a capital opportunity of distinguishing himself. His resources are sufficient to constitute one of the finest bands in the kingdom, and we shall be glad to find the Crystal Palace orchestra achieve such a reputation under his conductorship. ... Herr Manns is too intelligent a musician not to appreciate the nature of his resources and the requirements of his public. It may be safely predicted, that the music at the Crystal Palace will be one of its principal attractions within a short time after the instalment of the new director.
The rest of Manns's career was almost exclusively associated with the Crystal Palace. When he took over, the permanent band was a wind ensemble, from which, with four specially engaged string players, Manns improvised an orchestra of about thirty-four performers. With the backing of Grove  and the directors of the Crystal Palace he gradually expanded the band into a full orchestra, for which a new concert room was added to the Crystal Palace. Together, Grove and Manns made the Crystal Palace concerts the principal source of classical music at popular prices. The concert season ran from October to April, with concerts given on Saturday afternoons from 1855 to 1901.
Within months of his appointment, Manns gave the first London performance of Schumann's Symphony No. 4 in D minor and the British premiere of Schubert's "Great C major" Symphony.  His concerts featured the music of more than 300 composers. There were more Austro-German composers (104) than those of any other nationality, but British composers (82) came a strong second. Manns was the first conductor to introduce Arthur Sullivan to the English public, when he conducted the young Sullivan's Tempest music in April 1862. Manns later introduced early works by William Sterndale Bennett, Charles Villiers Stanford, Hubert Parry, Hamish MacCunn, Edward Elgar and Edward German. Thirty years after Manns introduced the Tempest music, Sullivan wrote to him, "How much do I not owe to you, my dear old friend, for the helping hand you gave me to mount the first step on the ladder! I shall always think of you with gratitude and affection." Among contemporary continental composers, Johannes Brahms (in 1863), Joachim Raff (in 1870), and Antonín Dvořák (in 1879) also first became known in England through Manns's Crystal Palace concerts.
Some fragments of a live performance of Handel's Israel in Egypt conducted by Manns at Crystal Palace in 1888 are among the earliest surviving recordings of classical music.
August Manns