[Histonet] Hard water.

[MRI]

Dear all,

In theory, we should all be using distilled or deionised water for 
making our formalin (assuming we don't buy it pre-prepared).  However, I 
know that some labs in my area are using tap water.  The water in our 
area is very hard ( >4.5 mol/m3 25°d) though it is pH neutral, and I'm 
curious if anyone knows what effects this may have on immuno and in-situ.
In our lab, we buffer our formalin according to the method in "Theory 
and Practice" by Bancroft and Gamble so I'm assuming others in the area 
do too... but I could be wrong, and I'm too frequently an optimist.
Should the buffers counteract negative effects from the minerals in the 
water or will they exacerbate the situation and add to the hardness and 
reduce the pH level?
Any ideas?

Thanks in advance,

Matthew.