I've never noticed green water to be very affected by temerature one way or the other. Daphnia are prodigous feeders of green water. I dount you'll be able to grow it ina tank with them. I always grow it seperately. -- Richard J. Sexton richard at aquaria_net Maitland House, Bannockburn, Ontario, Canada, K0K 1Y0 +1 (613) 473 1719