The ones that stick onto the glass. I use one on the glass to distract the livebearers, and another in the cave to feed the plecs! I think they're great! Just thought I'd recommend them.
i haven't used that particular type, but I use sera micro granules and sera flakes for my livebearers, plus sera which are like large crumbs in the same sort of flavours/colours as flakes, you shake them out of like a parmesan shaker (sorry, braindeath!!) and also use sera spirulina micro tabs for my malawis, they are also in a shaker thing! I'm really starting to like sera - just bought one of their filters, another of their CO2 tablet and plant fertiliser sets, and some Sera peat filter medium for my soon-to-be Amazon blackwater tank.