Don't worry about it if the worms are healthy. Likely just slightly different diet.

Agree with armoured............I've heard that a diet higher in carbon sources like cardboard and paper will produce castings lighter in colour. Check out the NW Redworms website - I think that's where I saw a video about your situation.

Harry

Thanks for the quick replies! I'll check out the website.

They will get darker with age. Not to worry.

Will happen if I fed my worms lots of carrot pulp from juicing.

The longer the worms work it the darker it will get. On the other hand the varied diet of different wormers can cause a variation in the color of the castings, no need to fret over that. That may be the advantage of using a worm factory 360 with multiple trays 4,5, or 6 trays in operation allow the top tray more time to be processed by the time it becomes the finished tray at the bottom.