In this experimental study, the effect of a modified 4-alternating pitched blade turbine (4-APBT) on isolated mixing regions (IMRs) was studied using a Newtonian fluid at low Reynolds numbers. The dimensionless mixing time, Nt(m), was measured using direct visualization of an acid-base reaction within the Newtonian fluid. The digital image analysis of the photographs revealed that the use of 4-APBT leads to smaller IMR structure volumes (less than 20% of total liquid volume) and reduced mixing time by 60% compared to those obtained with the 4-blade disc turbine (4-DT).