I dry dose some ferts in my 125. The regular measuring spoons work fine for everything but the small amount of phosphate I dose. For that I add 1/2 tsp to a graduated plastic liter container with a screw on lid filled with water. I can then just pour out a what ever amount I want to get the fraction I need to dose. I usually dose 1/16th of a tsp. If I pour out 1/4 liter from the container I've added 1/16th tsp. in solution. If I want to cut that down or increase it I can just adjust the amount of solution I use from the container.