+1...after I did a fishless cycle on my 40 gallon, I consistently use it to develop media for my smaller tanks. I just put together a 10 gallon betta tank and took about 1/4 of the mature media from my 40gallon to cycle it. I did splurge and add some more fish though hehe.....my betta seems to like swimming with my little school of rasboras lol...but i am watching out for ammonia spikesMature media really does make a world of difference, if only LFS's would sell that rather than bacteria in a bottle!