I am having some issues with the white pigment on my crystals. The White is muddy rather than a nice crisp white. I know the colour is improved with selective breeding which is step one in my program - I've picked out the whitest shrimp and will breed and cull to improve the colour but I'm sure that there must be some foods and additives I could use. Benibachi used to have a product called whiteup and Genchem has white pellets which I will try to purchase. My substrate is relatively new and I add mineral powder at water change - approx fortnightly. Water Calcium tests last year were in the right ratio . I am adding axanthitan - always forget how to spell that - but have found in research that it can muddy whites so that's not helping however I had the issue before I started to use it. The patterns on my shrimp are improving especially in my CBS where I am getting S, SS, SSS grade patterns but they are really culls because of the White. My CRS have improved from B/A grades to S and a few SS grade patterns but again with muddy whites. Pictures to follow. Anyone have any thoughts on how I can help improve my  stock? My obvious thought is to buy some good males and use them on my best females which will help but if I could improve my own stock without adding new genes I would prefer that.

Depleted active substrate can do this, as can illness.

Vacuum the top of your gravel and clean up any shrimp waste that you can. I also recommend using BetaGlucan to help the internal guts of your shrimp. Mine colored right back up after this.

Thanks for your input the substrate for the CBS is less than 6 months old and prior to that less than 2 years old, I dose Beta G weekly and have done for 2 years . I clean the top of my substrate weekly when i siphon out water. The CRS tank has new substrate now but the old was still buffering very well and the tank had Benibachi Micronecton mineral powder added weekly so those bases are covered. This is one of the new generation of babies from last season showing a great improvement . I am in the process of slowly catching out all the poor quality males - it's slow because the tank is big -it's a pity I didn't do it when I had them out for renewing the substrate DUH!  I have also culled a huge number of the CBS and will cull them again as it seems to be the only other thing I haven't done hard enough. I hope to see more improvement this season especially if I keep taking out the poorer quality males.