Eep! 25 is a high number to have with algae in the oceans. Best advice, keep an eye on it, get kids picking mushrooms, and worse comes to worse, pause the game when their health bars start going down and look for the mushrooms.
A lot of them like to say no when you start them on something new. I think its funny, they turn and stare out at you in defiance. Most go right back to the task in a few seconds. There are those that refuse to do about anything! If they are girls, I deem them breeding material when they are old enough.
PS Keep an eye on the game not the algae;))
I'm saving tech points for level 3 farming.