Here is the one I use.
After about 8 days I have thousands of critters swimming around.
I use an eyedropper and squirt them in my tanks.
I use lettuce,boil untill it gets broke down,the cool it off and put into a 1 gallon pickle jar.Make sure you treat the water you boil it in and the water you cool it off in.
I keep the light on it all the time,I have 3 jars just starting to clear,it is amazing how clear the water will become after the bacteria is gone!
Some say it is not needed to feed infusoria,but I figure it is snack food between meals.
Try it,you will be surprised how much infusoria you will get.
I have not been on for awhile,to those that read my post about my fry swimming strange,it must have been some kind of birth defect for a few of them,I lost the 3 that were swimming strange and culled a few more,the rest turned out fine!