Nickel plating problems can occur if:
- mixed metals are used in the loop (aluminum and copper)
- poor production of nickel plating
- if only distilled water is used in the loop (without any biocides)
The block or affected piece can still be used within the loop since this will not cause any problems to the other products or cause bad performance but if the appearance of the block is very important to you, the only option is to change the affected piece.