Converting micromolar to grams/L

Jun 2019
Hi, I'm facing a hard dilema right now. I need (though I don't know how) to convert 0.25 micromolar of Zinc Sulfate Heptahydrate to g/L, so I can weight it and put it on the water.

The molecular weight of the Zinc Sulfate Heptahydrated is 287.541 g/mol

Additional info: I need to run an experiment where the author achieves the concentration of 0.25 μM of ZnSO4·7H2O in a 10L water tank. I want to achieve the same concentration in the same amount of water, but I don't know how much (in grams) of ZnSO4·7H2O I will have to use for it.

I thank you all in advance!