It is higher, distinct, separate. Higher than what? Than the unmanifest mentioned before. The word 'tu', 'but', serves to mark the distinction of the Imperishable that is meant from that unmanifest. The 'bhāva' is the supreme Brahman named the Imperishable. Even though it is distinct, there might still arise the supposition of a likeness of nature; to set that aside He says 'another'. It is another, of a different nature; and that unmanifest is not within the reach of the senses. It was said to be higher than that one: higher than the unmanifest mentioned before, which is the seed of the host of beings and marked by ignorance. It is another, of a different nature. Everlasting, age-old, is that 'bhāva' which, when all beings from Brahmā downward perish, does not perish.
Contemporary English rendering of the Sanskrit bhāṣya, pending scholar review.