
Regarding the silica gel itself, if you have shopped for the stuff, you will soon find there are several options. Some are just plain clear/white and others have indicator colors added. The indicators look cool and serve a function, however there are some downsides. The blue indicators use cobalt chloride and are not food safe, but I've read it's a bit cheaper. I'm no chemist, but I would not use the blue silica gel beads due to the cobalt chloride colorant. The other choice for an indicator is orange (Methyl violet) which is also not food safe (for direct contact at least), but should be safer than the blue stuff. I think the best balance for use with my filament spools is the mixed orange and clear silica gels, since they contain only 5-10% orange indicator beads and the rest is just the clear stuff with no additives. If I had pets that got into stuff I'd go with the clear beads and skip the indicators, since using a humidity sensor can tell me when it's time to change or recharge it. I picked up some of this mixed orange and clear silica gel, which was a buck cheaper than Amazon, and includes free shipping. I wish they sold smaller sizes since I don't know if I will be able to use up a gallon of the stuff, but it's still cheaper to buy that size than try to get enough in smaller quantities. Having a gallon of the stuff also allows me to add more gel to my storage containers... but I will need to print more of the silica gel containers.