I added quite a bit of EC'ing to my nano tank that I plumbed into my 120. Things got very bad in both tanks. Huge dino bloom on the EC, and algae bloom in DT.
I'm certain there are silicates and other goodies in the material.
This was posted here before:
http://www.advancedaquarist.com/2011/3/aafeature
"The real surprise is the red line of Fig. 11; it documents the substantial increase in bacteria/mL for a control water sample that was not treated with EtOH. We simply removed about ½ gallon of water from the tub at the beginning of the experiment, and placed it in an open Tupperware container under fluorescent room lighting. This control portion of tank water was sampled for bacteria content daily just like the EtOH-treated larger tub water sample. Remarkably enough, the bacteria population in this control sample experienced a slower but still significant rise, increasing to a maximum of ~ 27x the original level after 3 days. What is fueling this bacterial growth? Since we have already determined that the bacteria population in this aquarium water sample is carbon limited, it seems reasonable to hypothesize that the Tupperware vessel itself is providing a metabolizable source of carbon! This vessel had been used in various water transfers previously, and it was rinsed with tap water and dried between uses. Could organic residue or bacterial films coat the plastic? Is the plastic itself "digestible" to the water column bacteria? These questions are not answerable at present, but the overall observation that the plastic container itself (or residue on its surface), and not necessarily the EtOH addition, can contribute to a significant increase in water column bacteria population raises some concerns about the interpretation of the results in Fig 10 (remember the caveat)."
There seems to be the answer to this mystery.