Neither of those are renowned for their hair algae grazing. Hippos are more planktavores than most tangs and the tomini a bristletooth that specialises in algae/detritus films. You might be lucky if you strip as much of the algae out as possible so they only have short algae to deal with (long algae is hard for most herbivores) but o think snails are your best bet or if you are feeling adventurous, an urchin.
Among the tangs, Zebrasoma seem to have the best reputation for eating long hair algae, Ctenochaetus (like your Tomini) have the best rep for film algaes and detritus.