I have moved cycled filters/media to new tanks and still had the diatom bloom. So for me, no, it didn't help at all. That's my experience though. I recently moved cherry shrimp to a new and larger home that had quite a bit of diatoms and they were all gone in just a few days. The diatoms, that is. The cherries were all lounging around with toothpicks hanging from their mouths.