Whoops! I never said that Hydra comes from Brine Shrimp Eggs! I read an article many years ago that most water carries the hydra 'bug' or whatever it comes from. I have just today read a few article regarding this by just doing a Yahoo search and most articles say that when the excess LIVE BBS is left uneaten it supplies food for the dormant cysts? or whatever to activate the Hydra. I use mostly RO and I assume that is the reason I haven't had this pest in over 6 or 8 years as I too go through about 1 can of eggs a month.
I also do not take any credit for discovering that Fluke Tabs eliminates Hydra. That information was given to me by our good friend Delores Schehr at Wet Thumb Aquatics.