Personally? I'd be pouring bleach or Liquid Chlorine (same as bleach, only stronger) in to get the FC up. The Tri-Chlor tabs take longer to release their chlorine. BUT DO NOT POUR THE BLEACH ON THE TRI-CHLOR. If there's a floater or you have tabs in the chlorinator, it's OK to pour the bleach into the return stream so it goes into the pool, but do NOT pour it into the skimmer!