From my experience. Not anything like OG Biowar..
There is only lactos bacillius active in Em.
I did receive and informative email from "teraganix.com" stating that EM1 can be used in hydro to keep drippers clean.
I tried in my drain to waste and did not see any extra benefit from using it.
Now soil is a different story though.
Another benefit I saw was the EM1 ate PM for breakfast and helped prevent an outbreak.
There isn't anything bad that is going to happen using the lactic bacterias in EM-1 in DWC. They are anaerobic and would keep bad anaerobic bacteria from taking hold. It does eat PM to shreds, I use it as a preventative maintenance. I would stretch it using molasses following the instructions for activated EM-1.