Tree Frog Humidity Help

[emseeKAY]

So i am new to amphibians i bought myself a Red Eyed Tree Frog and have put her in an exo terra small rainforest terrarium, i am using a 50w exo terra tropical baskin bulb and have misted the tank throughly, i am using sphagnum moss substrat and have some branches and plants in the tank, but the humidity will only hover around 50 or so and i was told to keep it more around 70 can you please help? ive looked everywhere and nobody has given me any answers!!!!