i used it in my nano till i ran out. lol. i picked some up from one of the shows a while back. i got them for $3 each at the time. i think i must have bought atleast 15 tubs. they were convenient for me. i liked that they were already in a mesh bag and ready to drop into the chamber. my tank was crystal clear when i was using it. i never had that green tint in the water using chemipure elite. next time i see them at one of the shows, i'm gonna really stock up... they're kinda pricey at the lfs.