I just watched a video of a student playing a piece that I love. Instead of focusing on her music making, I was distracted by the tension in her hands. Little hands clutched in a fist, fingers leave to pluck, then returning to their frozen grip in her hand. It's uncomfortable to watch and likely more so to play that way.
Are you relaxed? Every harp technique I can think of includes some method to keep hands relaxed. It's not healthy to work with constant tension in your hands. Muscles and tendons need to rest.
It's important to release tension as soon as you leave the strings. The method you play doesn't matter, or whether you play pedal harp, lever harp, wire harp, tension is not good for you.
Practice relaxing you muscles each time you leave the strings. At first it's a separate step all its own, play a string, relax the hand, place, play again, relax again. Like anything else, the more you do it, the more second nature it becomes. Renie called it keeping the hand supple.
For many of my students, it helps to think about being graceful when playing. Strength is still possible within a graceful move. Tension inhibits gracefulness. Cluing in to how whether or not your movements are graceful can help you learn to release tension.
Are you relaxed? It should show in your hands. If it does, it can be heard in your playing.