....Hard to find, checked with Tetra, lady on phone said product seems to be phased out! What?? This product is like viagra for fish, it is excellent, also the boosts there colors and has vitamins, fish are very active and look great, if you find some in your lfs, give it a try...water turns lime-orangy color for the first 24 hours then color when Iodine content stabilizes, water is clear..one of the few products that really deliver, too bad it may have been phased out....just like there diatomagic filter