According to Andy's book, if you have changed settings, moved to a different location OR see that the ground has changed, you should perform a noise cancellation. Seeing as you are going from dirt to sand, for optimal performance you probably should do a noise cancellation. I generally do a noise cancel at least once every half hour just to be sure that the Safari is performing at its best. It only takes 20 seconds, so why not... The Safari does have automatic ground balancing, but supposedly it is the noise cancellation feature which initially checks both ground mineralization and EMI before selecting the optimal set of frequencies to be used by the Safari. One last thing about noise cancelling, there should be no metal next to or under the coil while doing so. This information is also from Andy's book.