IME I wish I would have gotten mine off of NH BBS earlier than I did. My first few batches that I went too long with it, I could tell. I had SFS happening all too often. The last batch I had much more success with. Are you gut loading the BBS as well? I was feeding the BBS phyto on hours ~36 - 72. I would then have a new batch ready for feeding time. If you aren't gut loading, I wouldn't recommend feeding the BBS much past that 36 - 48 hour mark or you may start seeing SFS. I have never had as many as you have at one time. It must be thrilling. I know it was for me as I watched them grow. You'll miss them when they are gone too. I called the LFS store this week to see how mine were doing, he told me they were all doing fine with the transition to his tanks and were all feeding voraciously. I hope they sell to a good reefer or breeder.