I've been using that stuff for about 6 months now. I can't really say that it has done any good since i've been using it along with DT's too. But, it sure hasn't done anything negative. In fact, i think my tank is doing the best its ever been! Perhaps its coincidence or maybe not..either way, i continue to use it since i've had good results. Its very thick and dense, kinda like syrup. It must be diluted w/ water prior to adding to the tank. A little bit definitely goes a long way.