For my clam population I feed DT's and alternately mix with KoralVitF. Dt's is the best live based phyto you can feed clams and the KoralVitF is a yeast based product that Knop suggests. My clams really get into feeding after I have fed using the KoralVitF. Why such a response I have no idea but they really do.

The only thing I have against any of the Kent products is they are dead cultures. I also recently have started using the frozen Cyclop-Eeze but this phyto is too large for clams to utilize, but the sps love it.