That slider bar is the variation in the KELVIN scale not the color spectrum so warm (2K) to cool (6K).
If this is an Osram bulb you should have a small color wheel in the top box of the device - you choose COLOR here.
Within ASK ALEXA there are 3 color choice that Michael has included that may fit your bill for a “white” type light. Those are: vanilla, white. amber.
Perhaps you can try those 3 and see if they fit your bill for a “shades of white”
Thanks to @femwitjava for answering this. There is an option to add your own color, and I am contemplating adding a few more slots as people really like setting up their own colors.
Thanks guys. I’ll give into the documentation to see how to add my own color and I’ll post back here with the settings for ‘day light’ and ‘moon light’ in case others are interested.
I would be open to adding more colors, but the caution here is that you would have to memorize all of the colors available to use them…
Agreed, but I think it’s less about memorization per se and more about just picking a color and ‘holy crap that worked.’ I noticed there is a lot of crazy named colors in there already 
Hmmm…good point…I think a compromise for this is to add more custom slots so the user can add what they want (which is easier to remember than, say, carnation, or vanilla).
Please note, I have updated the code to 2.2.0. Please use this codebase for all installations: