Definition of merger
If you play games at very high limits or if you always play against the same excellent players, yes, it will be important to merge your range to avoid being readable. However, if you are playing against amateur players who have a lot of weaknesses, you don't need to merge your range; instead, you need to exploit your opponents' weaknesses. For example, you are on the river in position and it is your turn to play. If you are against a very conservative player who folds too easily, bluff him often! If you have a good hand, bet small!? Conversely, against a player who calls too much, don't bluff and bet bigger on your good hands only.