could you tell me more about Roots 2 :
-Why stains
-price
-size of the bottle/ container / weight
and why cannot be used indoor?

There are products in it which probably contain iodine and humic acid. i
imagine these are what cause the stains.
It comes as a powder which you add to the water. I don't recall the price. Ask
Dave Lowman.
The only reason I don't use it indoors is because it stains the shelves &
everything it touches.
Iris,
Central NY, Zone 5a, Sunset Zone 40
"If we see light at the end of the tunnel, It's the light of the oncoming
train."
Robert Lowell (1917-1977)