I've always found it frustrating having to "trash" perfectly good chems when you buy new ones anyway. I wish it was a bit more like plant tycoon where you have a choice of any 5 different chems at a time, makes far more sense. I guess fish tycoon came 1st and plant tycoon improved on the original. I don't suppose there are any plans to upgrade the program now so guess we are stuck with it. still love the game though, so it can't be all bad