[Histonet] how often do you change your hematoxylin?

[Meryl Roberts]

We are currently using a vintage solution, and the manufacturer states that it should be good for 2500 slides. We are not a high volume lab; and currently I am finding that the longest I can stretch it out for is 2 weeks max, in which time we have stained less than 1000 slides. How often does on average do you change your hematoxylin? Do you think maybe it could be getting diluted by water dripping from the slides; or maybe it is oxidising in the air? Thanks, Meryl