The water changing color is such a cool effect.
The chemicals I use are...

Ferric Ammonium Sulfate mixed with Tannic acid will cause the water to turn black.
Then mixing in Oxalic acid will bring it back to clear.

These are all powders and very safe.
Ferric Ammonium Sulfate is also called Iron III.
Tannic Acid comes from tea leaves.
Oxalic Acid is the chemical they use in these oxygen cleaners, such as Oxyclean.

And if you want to get them cheap...
You can get everyone one of these on eBay.

Randi

Has anyone in the UK managed to get hold of this? I have seen little kits in Toys-R-Us for "magic sand" but the bottles are very small and only contain the fluorescent colours which don't appeal to me much. Dunecraft's "Space Sand" is available but only as far as I can see in red.

There is someone on "The World's Online Marketplace" who always has several sets for sale, including bowls, I believe. I can't vouch for the product, but the whole set is there, including chemicals.

Anyone know whether "moon sand" is the same stuff? Also "mars sand"?

It's all the same stuff.
It's sand that has been exposed to trimethylhydroxysilane.

Here is a place that sells a tri-color pack...
http://www.kleargear.com/2040.html

I have wondered, never tried, that if you coated sand with Scotchguard if it wouldn't do the same thing.

Randi

Thanks.
I have read that Scotchguard does work.
I wonder whether the amount of trimethylhydroxysilane makes a difference - eg moon sand is supposed to be mouldable even when "dry"
Thanks for the supplier link but I don't think shipping sand across the Atlantic is a realistic proposition.

Be wary of the pre-packaged versions. The dealers seem to send sand and scoops and no chemicals. Mixing those would have to be a drag. The Magic Auction does sell pre-mixed sets of chemicals for about $1 per use, and this seems like the way to go if your chemistry set is smaller than your close-up case. Check their stage magic area.

I found "sculpting sand" in Hawkins Bazaar in the UK at a reasonable price (though small quantities only). However, I don't think it will work for the trick. It stays dry (though an annoying amount remains on the surface of the water) but it doesn't clump together in a manageable ball - so it will mix up with the other colours.

The stuff I have seen magicians use will clump if you squeeze it just as you drop a handful into the water. You can then appear to mix the sand up but actually it remains unmixed in a ball. I believe the method for making this uses sand, wax, and a lot of heat, but does anyone have the actual recipe and method?

One thing I have observed is that most magic suppliers that sell the chemicals for "Sands of the Dessert", (aka "Sands of the Sahara", "Hindu Sands", etc.) all recommend prepping the water beforehand with the Tannic Acid.

This typically gives the water a strange yellowish tint which I find annoying and some audience members have commented upon.

Whenever I've seen other magicians perform this trick, the water is always crystal clear at the onset of performance.

After some experimentation, here is my method that has given me consistent, crystal clear water and deep black (extremely dark purple), opaque water throughout.

I start with 1 Gallon of clear water. I typically like to buy distilled water for this purpose. Using distilled water ensures there are no other chemicals or minerals that can adversely effect the intended result.

I then fill an empty size 000 gel capsule with the following "recipe" for "Black Water"

1/16 teaspoon
Tannic Acid
Chemical Formula: C76H52O46
Chemical Abstracts Service (CAS) Number: 1401-55-4
Grade: Reagent, ACS

1/8 teaspoon
IUPAC Name: Ammonium Iron(II) Sulfate
Other Names: Ferrous ammonium sulfate, Ammonium iron sulfate, Mohr's salt
Chemical Formula: Fe(SO4)(NH4)2(SO4)·6H2O (hexahydrate)
Chemical Abstracts Service (CAS) Number: 7783-85-9 (hexahydrate)
Grade: Reagent, ACS

I then fill a second empty size 000 gel capsule with the following "recipe" for "Clear Water"

1/4 teaspoon
IUPAC Name: Oxalic Acid
Chemical Formula: (COOH)2
Chemical Abstracts Service (CAS) Number: 6153-56-6 (dihydrate)
Grade: Reagent, ACS

This allows you to start off with perfectly clear water at the onset of performance.

The gel capsules make it easy to get the chemicals into the water when appropriate with consistent behavior/results.

The end of the routine is when the water is less clear, but this typically goes unnoticed, especially after a proper back-story (aka patter) build up has been given.

I've also had other vendors (i.e. Hindu Sands produced by House of Wonder) provide Ferric Chloride. This stuff is terrible for this purpose. It's extremely corrosive and even the slightest amount of moisture ruins it for use in this particular application). When House of Wonder sent it to me, it was already ruined upon arrival.

I typically order my chems through a proper chemical supply wharehouse or with enough due diligence and research on my part, I will order from Amazon.

Cheers and happy magishing!

I've read descriptions of this trick. I've always wondered, what happens to the "mixed sand" when you make the water clear again?