The care instructions for Tiger shrimp (including OEBTs) are sort of varied. While they 'can' do well in higher pH and with slightly higher temperatures (compared to Crystal Red Shrimp and other Bee shrimp which is the reference point that most people here are using since they are the most commonly kept of the more 'difficult' species) most people here seem to keep the tigers in tanks that are set-up along the lines of what you would use for Crystal Red Shrimp. It might be a bit of overkill, as the tigers are more tolerant of different water conditions than CRS are, but people seem to have success when doing so.
You can get the tiger shrimp to survive in harder water but you might have trouble getting them to breed so most people just put them in softer, cooler tanks like they use for Crystal Red Shrimp.
They do seem to be more hardy and breed in a variety of conditions. Looking at the poll here http://www.shrimpnow.com/forums/poll...ults&pollid=22
7.4 range is the highest answer from tiger keepers there.
I just moved my tigers from a tank that was about 6.8-7.0pH to another tank with my cherries that is around 7.4pH, so I guess I'll see if I get babies in the higher pH or not.