I became interested in Haydite after reading this thread.
I live close to Sugar Cone; and therefore close to his supplier, Northshore Bonsai. I had some problems reaching them, so in the meantime I contacted the manufacturers of Haydite directly. They were very helpful, and sent me generous free samples of the two versions I believed would be most useful - the Greenhouse Blend and Bonsai Grade.
According to the manufacturer, the Greenhouse Blend is "primarily of 1/4"-1/16" particles sizes with nearly all dust and the very fine particles removed", and looks like:
Looks good to me! But what I received is:
The color is obviously not the same as depicted on their website. Neither is the size, and there's so much fines that I didn't even try to rinse it. I'd lose at least half by doing so through any reasonable mesh.
On to the Bonsai grade, described as "about ½ to 1/4th the size of a pencil eraser". After rinsing and drying, I got this:
The size is correct and there were very few fines. But it still doesn't have the color I expected, either from the manufacturer's pictures or the ones Sugar Cone posted.
One of my issues with common calcined clay substrates is their extreme light weight. I was hoping the Haydite might be heavier, so I did some comparative tests of it versus Schultz Aquatic Plant Soil (which is just repackaged Turface). 1/2 cup of each were immersed in water for an hour, then strained and weighed:
However, some of the Haydite was floating, so I figured it hadn't fully taken on water. It took three days for all of it to sink. That would be rather irritating in an aquarium! I waited two extra days just to be sure, then weighed both again:
I must say I'm disappointed. Neither color nor density was what I expected. The color is similar to the now-discontinued Soilmaster Select Charcoal and Turface Gray, which has its own appeal; but it's just not what I'm looking for at this time. I may still end up trying Haydite in a tank at some point in the future, and will report back if I do.