Terrible condensation/mold? What to use to prevent

DampRid or Humidri, two buckets of DampRid worked for us with 4 months in a damp cave, but if you're going 5-6 months the storeage place recommends the Humidri which is a bit more expensive but apparently does a better job (I believe it's a pail of the silica gel beads like what you get in many packages like shoes that a transported in shipping containers)