[Histonet] variable staining of alcian blue

[Rui TAHARA]

Hello, 

I am staining paraffin sections (10 microns) with Alcian blue and Nuclear Fast Red as standard protocol as below. 
The problem is that I see some sections stained with alicain blue show some variability (hope i am able to attach image); 
alcian blue stain are washed out in some sections even in the same slide. Those sections show pink color in the cartilage. 


Clearing
dehydrate
1% Alcain blue (PH2.5) 30 mins
dip in tap water
running water 2mins
dip deionized water
0.1% Nuclear Fast red 5 mins
dip deionized water 30 sec X 2 
95% ethanol 1min
100% ethanol 1 mins X 2
clearing 

Is this something to do with filtering alcian blue or nuclear fast red? 
I filtered alcian blue using needles to eliminate a big undisolved particle, but I did not filter the nuclear fast red since it seems all dissolved well.
also I rarely had the problem last time i used the same staining. 
I know i need to filter with filter paper but when i tried, even with non-fine filter paper, it absorbed too much dye and was not successful.  


I tried to wash nuclear fast red with running tap water 1 min and dip in deionized water intead of twice wash of deionized water as described above. 
However, variable staining of alcian blue still present. 

Does anybody have same problem before? 
I appreciate any suggestion to solve this. 

Thanks. 

Rui