May 1998/February 2020
I was tidying up some files on my computer and tripped across this curious bit of research prompted by a question back in spring of 1998. I have no idea where the original question came from, but the results are amusing, and quintessentially me. I wasn’t even sure I was the author until about half-way through re-reading it; I certainly have absolutely no recollection of doing the research.
GRay™ wrote: “We have a 25,000 gallon swimming pool. How much kool aid (I was thinking a sams container or two) would it take to change the water to orange?”
Somebody else made a comment that was, sadly, redacted. Probably about the choice of color.
Good point. Don’t use red or purple. Lemon-lime will probably be the most resistant. Hmm. Let’s do some math.
One packet of Kool-aid is usually used in two quarts of water. I’m willing to bet that a pretty vibrart color could be seen at 10-20 times that dilution. Let’s say 16 times. That’s four gallons.
Hmm. 6,000 packets of Kool-aid.
that’s not good. Time for an experiment.
The darkest color in the fridge was Black Cherry.
1/4 cup in a pitcher, then enough water to make two quarts. That’s 32:1 dilution. It was pretty pale, but if you were looking through four feet of it, you’d probably still see the color.
Of course, if you put Orange in a pool with a blue tinted bottom, it’ll just look slightly muddy.
If you want a really vivid color, you’ll need a much higher concentration.
It looks like you can’t go any higher than 10:1 to get a decent color. That’s 10,000 packets of Kool-Aid. Not good.
I have some of the boxes that packaged Kool-Aid comes in here. They don’t state how many packets in a display box. I’m estimating they hold 60. So you’d need about 160 display boxes of Kool-Aid. Hmm. More than $2,000 at retail. Ick.
However, Black Cherry’s colorant is Red 40. This is the same dye used in red food coloring. A quick check shows that Orange uses Red 40, Yellow 2, and Red Lake 40.
Because chlorine will bleach out Red far far faster than any other color, Orange is now doubly a bad choice. Better switch to blue or green. Although Blue will probably just make the pool look deeper, and Green would make it look like it had algae. Hmm. Well, you might have to test it.
The tinting strength of 1/3 drop of Red 40 food coloring is about the same as 1/4 cup of Black Cherry Kool-Aid.
One packet makes 32 1/4 cup units, so is equivalent to ten drops of food coloring.
There are 100 drops in a teaspoon, give or take.
10,000 packages of Kool-Aid are therefore the same as 1,000 teaspoons of food coloring. 3 teaspoons = 1 tablespoon 16 tablespoons = 1 cup 16 cups = 1 gallon
It would take approximately 1.25 gallons of food coloring to dye a 25,000 pool a reasonably dark color. Tinting it could be done with 1-2 quarts.
You should take two quarts of water from the pool, put them in separate containers, and add one drop of Red to one and one drop of Blue to the other, to see how quickly they’ll fade. The red may hold up better than expected, although I used to do a magic trick that relied on the fact that enough chlorine to completely bleach Red food coloring in about ten seconds would take half an hour to burn off Blue or Green.
I would be delighted if somebody else were energetic enough to duplicate my experiments. Ideally, what somebody needs to do is put three or four gallons of water in a bathtub and add one packet of Kool-Aid (or ten drops of food coloring), then keep adding water one gallon at a time, taking notes as to how vivid the color appears, to see if my results are reliable on a larger scale.
Pools are typically chlorinated at a level of 1 ppm or more. (I think. It’s been a long time since I looked at a pool chlorination gauge, but I think that was the calibration...) To simulate pool chemistry, you’d need ... hmm. Household bleach is a 5.25% solution, but I don’t know that percentage (by weight? by volume?) corresponds to Parts Per. If it does, you’d need math math math two drops of household bleach per gallon of water.
This seems rather low.
Thought experiment two: It used to take three gallons, more or less, to initially chlorinate our pool. We were using concentrated solution, 12.5% chorine. The pool was, um, hmm, a 40x10x5 oval. (I think.) Roughly 2000 cubic feet. Great, now how many gallons in a cubic foot. Handbook of Chemistry and Physics 7.4281 gallons. So it was a 15,000 gallon pool.
Geez! And you’re trying to color a 25,000 gallon pool? That’s huge! Is it a public pool or something? *Our* pool was the biggest in the neighborhood by quite a bit!
Where was I? Oh, yes. math math math If it was a 15,000 pool, then creating chemistry in your bathtub equivalent to the chlorine treatment we used to get it started after refilling would take about 1/4 teaspoon of household bleach per gallon of water. That sounds more reasonable to me.
Argh. OK, I can’t resist. Off to the tub!
Oho! I may have grossly overestimated the tinting required to show a good strong color. Three drops of Blue were enough to add a distinct blue tone to ten gallons. At that rate, 1.5 cups of food coloring would color a 25,000 pool.
Now, to repeat the experiment with actual Orange Kool-Aid and bleach.
Aha! One package easily stained 30 gallons a fairly obvious orange. math math That brings the package count down to about 800. Given how slowly the color was weakening, you could probably do 1:100 (one package per 50 gallons) successfully, requiring a mere 500 packages for the swimming pool.
The food coloring results corroborate this, since 1.5 cups of food coloring = 750 packages of Kool-Aid.
The bleach has not yet had a visible effect on the color. According to the hypothesis, it will become less orange and more yellow over time. Without waiting for the results, I’m willing to bet that it’ll be orange for at least an hour, and probably quite a bit longer than that.
So, there’s my final answer:
It takes 500 packages of unsweetened orange Kool-Aid to dye a 25,000 pool.
P.S. If you actually do this, I’d love to hear what the results were!
To the best of my knowledge, I never did hear back from the person who asked the question.