Anonymous One wrote in
:

My wife and I have a very unusual situation. A plastic bottle of a
"Cactus Food" tipped over and sat in the solution for a day or so. It
is a slightly low spot of our concrete patio so it did not evaporate
as quickly as it might have on an area that did not "pond." The
solution is comprised of the following ingredients:

1.0% Nitrate Nitrogen
7% Available Phosphate (P 2 0 5)
6.0% Soluble Potash (K20)
1.0% Calcium

Derived from: Ammonium Nitrate, Calcium Nitrate, and Potassium
Phosphate.


What has happened is that it has stained our concrete patio, and where
the bottle had layed down, it has etched a groove in the surface of
about 1/2" or so. When we called the company they took no
responsibility, in fact they were rude, saying that this had never
happened before and it was impossible. My wife talked with someone in
a concrete manufacturing company who said this type of solution could
damage concrete. I did not know where to turn so I am curious about
what you folks in the chemistry community might think of this. Also,
it is odd. Since this has happened, every morning the area where the
spilled occurred appears wet, even though it is not currently raining.
It almost looks like moisture is being leeched out of the air and
drawn towards this spot? The person in the company did tell my wife to
drench the area with bleach, but that did not help at all. Any idea,
suggestions, etc. would be greatly appreciated. We do not even know
who to ask to help us as we do not want the concrete to degrade now
that it has been deeply etched. Thanks in advance for any help you
folks can offer.


... When we called the company they took no
responsibility,


Why should they? You think they should be testing cactus food on patios
before selling it? What else should they test it on? Maybe roofs,
trampolines and iguanas?

They probably figured you were trying to squeeze some bucks out of them.
Maybe line them up for a legal damage claim.

What if someone in this NG tells you to try something and it makes it
worse? What then?

Since this has happened, every morning the area where the
spilled occurred appears wet,

Plain ground clay cat litter will suck many liquid things out of
concrete. Frequently used to remove oil on driveways. Remove oil by
putting some on, grind in with your foot, let it sit over night. Sweep
up next day. Repeat until it no longer will remove anything else. Live
with what's left. Disclaimer: Should you decide to try this on your
patio keep in mind it could make they eyesore worse. Not practical on
patio to hide it by parking over it.

it has etched a groove in the surface of
about 1/2" or so.

Live with it or repair. Sometimes a repair is worse then the original
eyesore.