Although DT is live..it does'nt give you any reason to overdose. All live stuff will die eventually. They might just die in your tank after going thru filter media, pump impellers etc...
For me I dose everyday and i already notice I get slight green algae on my front glass everyday.. I just leave the skimmer off during feeding...after 3-4 hours I on it again...skim out the excess phyto.