Removing water to reduce humidity help please?

I think you need to take the actual relative humidity into account. Relative humidity is a measure of how saturated the air is with water vapor. The important thing to remember is that relative humidity is a function of temperature. The amount of water will vary between temperatures, even if the relative humidity stays the same. I suggest the first step is finding out the amount of water the volume of air can hold at 20C and 93.5 percent. Then calculate how much moisture is present in the volume of air at 27 percent. The difference is the amount of water which must be removed to drop the relative humidity.