I just ordered a bunch of Erio and they would be my first experience with them. How often do they send up flower stalks in everyone's experience?
Mine will be in high tech with very high PAR and tweaked EI dosing if that makes any difference.
A lot of times, Eriocaulons will all flower together, especially when they have been subjected to some kind of environmental change (such as being transferred to a new tank). If you yank all the inflorescences and things stay stable, they usually won't try to flower again for quite a while. If that does happen, just repeat.
I agree with Tinanti's statement that they tend to all flower about the same time.
You did not state if the plants are submerged or emersed but in either case they do not die after flowering. Flowering does take a lot of energy from a plant however so I remove the flower stalk before it blooms to allow the plant to save the energy it would use for blooming and seed production for better growth and strength.
What I do is I remove the plant from the substrate, clean the roots, then take a single edge razor blade and carefully cut the two crowns apart being sure to have some roots with each crown......then replant.