Never saw that for powders, honestly by looking at it, I have hard times to see this always "working" properly.....
Though I have seen these for liquid detergents and softeners.... they didn't have much success also...
Currently, there's a floor detergent from Sutter company that re-proposed this auto dosing bottles (that you may anyway see in some commercial/janitorial products) you'd push the bottle and the little chamber would fill to the line corresponding to the liters of water you have to diluite it in... this thanks to a pipe located near the handle...
Also the same company along with the auto dosing bottles made kinds of ultra concentrated liquid refills in a soluble film, you'd just drop them in the bottle, add water and shake..... they should be more economic according to them....
I have tried them, and didn't find it to be as effective as the normal un-diluited liquid, by the way that is not even my favourite brand, which is either Ajax, Spic&Span and Mr Clean, but the refill result it's just not the same thing....like BTW it was for softeners back in the days when refills to diluite were very common..now they are all super concentrated meant to be used pure, more fluid.... though they just don't give the same of the big jugs, though they made them cheaper than what refills were once which is good....I remember the old Milk-like cartons from Downy/Lenor and it was very thick, but if you watered as directed what you got was not the same....
As for the safe measuring bottles, I am not a big fan..I just don't care.. I would just pour it from the bottle as I know how much it's needed and I can kind of eye meter it.... even without having to dose it,...I just find it's easier....of course one need to be practic about it...
[this post was last edited: 10/10/2014-16:37]
