Umm. I never really measure. Just a good lug lug for 50 gallons. If i need more i add more. Im sure you wil find some measurements on line as well as people who say not to use it. It works well for me. As for the dawn, i think a teaspoon in a large spray bottle.
Sorry it took me so long to notice that I had a pending message. I also would be worried about it. If you look at GPS frontiers past "greenhouse" posts, he has pictures of a filter system he built using parts from Home Depot. Also you can use some hydrogen peroxide to help keep the yuckies out of the tank. I don't use pesticides or fungicides. I only use dawn diluted in a spray bottle, spray in the morning and wash it off at night. Takes care of all the bugs. I answer my facebook messages a little faster either at Tracy Garrison Christensen or Tri-City Hydroponic Gardeners.
