What do you want to use them for?
We dont get Krill in Australia, and GloToobs are hard to come by, but I have 3 GloToobs and some Glowrings.
I have a Blue, White and Amber GloToob FX and I am very happy with them.
I have Blue Green and Pink GlowRings, and the Green is the best by far.
If you are on eBay, I can recomend sellers called "raven-tech" in the UK and "reshef-21" in Singapore. reshef-21 also sells through candlepower forums under a different name, and he offers different sized Tritium vials there as well as the Glowrings so you dont need to use eBay. He is very aproachable and good to deal with.
If you search this forum for Tritium, you will find a post by Groo about Tritium Safety Markers which he found in the US. They are a bit bigger than the GlowRings. He can tell you more about them if you send him a PM.