i feed mine DT's, i turn off the skimmer and filter for about an hour or two after i feed. The reason is becuse if i dont then the skimmer goes crazy with all this green foam which i assume is the DT's, after an hour when i turn the sump back on its still skims out some green just not as much. my 2 cents is to turn off you sump or whatever filter and skimmer you have when feeding phyto. so that your corals can benefit from it