It is for filling test tube with water. Is it safe using tape water? What about rain water?
Thanks
Mst people recommend de-chloinated water, Personally, i have never found any difference but you could let the water stand open for a couple of days indoors, the chlorine gas will escape into the air leaving as such e-chlorinated water.
Again, i personally wouldn't use rain water as its full of all sorts of toxic particle from the air,