Do we need to employ a professional strata manager?

No. There is no legal requirement for you to engage a professional strata manager. You can do-it-yourself with support from an online program such as OurBodyCorp.com.au. Remember that in every scheme it is the owners who are responsible for its management. This is the case even if you have a strata manager. There are certain owners corporation functions that cannot be delegated to the strata manager, such as setting levies, electing the committee or changing the by-laws. (Strata Community Aust).