[Histonet] Hematoxylin too dark

[Shea's]

 Our new lot of Hematoxylin is too dark and especially overstains the mucins in colon bxs and even membranes/umbilical cord. 

Reducing the time from 3 minutes to 1 min helps some, but it  the inappropriate dark staining of the mucins is a real problem. We are also getting a film of hematoxylin on the on the slides. Thanks to the Histonet archives, we solved the problem by lowering the pH of the hematoxylin... added glacial acetic acid (about 12.5 mlsGAA/ 500mls hematoxylin). This is fine for a quick fix, until the manufacturer or we figure it out. We do not have a pH meter, which makes this tricky for a long-term solution.

The program on Sakura DRS places our slides in running tap water (about paper pH 7.2) before it lands in hematoxylin. 

 

My question is, does anyone use a DI acidified water station before it goes into Hematoxylin? If you are going to get carryover from water into a Hematoxylin, why not make that water DI-acidified so it does not raise the pH of the Hematoxylin? Would that give more constant staining from day to day after prolonged use (we change the hematoxylin after 2200-2500 slides.) or does it really matter, because a pH 7 water, only dilutes the Hematoxylin, not alter the pH?

Also, we use a Clarifier I (alcoholic based) after the hematoxylin and running water wash. Do others find that  a 4% aqueous works better?

All suggestions welcomed.

Thanks,

Jan