FWIW, when I had a caulerpa farm, running the lighting 24/7 never stopped it from sporulating (aka "going sexual").
In answer to your question though I sort of doubt there would be a noticeable difference in nutrient export going 24/7 vs not. I think what would make a telling difference is the size of the chaeto growing area so that there's more of it, but otherwise probably it's only a few percentage points different. That's my completely uneducated guess anyhow.
