eco-complete raises GH. So are discus out of the question?

Hi everybody...
My goal in setting up my 55 has been to get to a point where I had a
well planted tank with discus. I knew this would be work, but it seems
I may have missed a key point... although the KH and GH of my tapwater
are around 5-7 degrees, the eco-complete substrate I use for plants
raises the GH in my aquarium to 16 degrees or so (It may have also
been raised by a dose of flourish I added---I could avoid adding this
in the future). Does this means I have to abandon my dreams of keeping
discus in the tank, short of emptying the tank and ditching the
eco-complete??

My setup is:
55 gallon, eheim 2215 for filtration, eco-complete/gravel 60/40
substrate, DIY yeast co2 (just one bottle now), and the "starter pack"
from www.freshwateraquariumplants.com, with extra plants and two nice
big amazon swords I picked up from a shop the other day.

Thanks very much for any advice,
Wes