Keith your KH is good so you just need to crank up the CO2 a bit more...the ph will drop with more CO2. You havent added fish to your tank so there is no harm in "practicing" right now. Increase the bubble rate going into your reactor and retest tomorrow. If no change , crank it up a bit more until you get it to drop... thats a big tank you got and it will take a good amount of CO2 to effect the water.
The best part is you dont have to worry about a ph crash and fish...and the plants you have in there wont mind it at all.
BTW, Did ya get that plant order yet ? roud:
Also, when you test the ph from the tank, test it immediately, dont let the tube sit around and then test, the CO2 concentration leaves the water quickly and can give you false readings... especially with a high ph like yours to start with.