Feeding Reef Roids Problem

Hi,
How do I measure out how much Reef Roid to feed my 10 gal tank? I think I am overfeeding the way I do it. But the measurement is so small (.25 tsp/25 gal right?) how do I mix it?
By my calculations I need 1/10th of a tsp for 10 gallons. But how do you measure such a small amount? Even if I could mix it and keep in the fridge I would still need to measure out .01 of a tsp to make a gallon, and then feed .1 of a tsp at a time.

Thanks.