Step 1: Recall accounting principles.
When there is a decrease in the value of assets, it is treated as a loss and debited to the Profit and Loss Adjustment account.
Step 2: Evaluate the options.
- Debited: Correct answer, as a decrease in asset value is treated as a loss.
- Credited: Would apply to an increase in asset value.
- Added: Not applicable in this case.
- Equal: Does not apply in this context.
Step 3: Conclusion.
Thus, the correct action is to debit the decrease in asset value.
Final Answer: \[ \boxed{Debited} \]