Finally!
A use for my Horticulture degree here.
I believe that it would be good for your plants if it were from a freshwater tank. Unfortunately, there would be too much salt in skimmer liquid from a marine tank to be healthy for plants. Salt is a problem that most plants cannot deal with. Basically, only a few specialized plants species (weeds) can grow in a salty environment. Sorry.
Good luck.
-Christine
yup. i agree with zafira. too much salt. otherwise, would be great. i don't have any formal training in horticulture, but i've worked as a landscaper (among other things) for 6 years.