At 60 ppm, or approximately 3 GH, you might be okay with some tigers. Otherwise, would recommend bumping it up to 5-7 GH (90-125 ppm) if you want to keep Neos. (or other tigers)
Or you could stick with amanos... should be fine, however, if you have males and females, then the offspring will die in freshwater tank. They are not easy to raise. If you got all females, then no worries about offspring, and the girls are larger, too!