Re: Diatomite comparisons?
Posted: November 28th, 2011, 2:19 pm
Hi Scott
I don't mean to offend but the ability to keep pot temps even is not confined to akadama. See, I agree with what you are saying with regards to the importance of keep pot temps constant and even. But, diatomite is porous like akadama.
Diatomite is inherently porous. That's why it's used in filter media and as an absorbant in spill kits.It's porous like a sponge. At one point in my life, I even was trained to use as Fuller's earth (basically ground up diatomite) to absorb chemical warfare agent on personal clothing and equipment.
Thus all the properties that akadama has in terms of keep pot temps even and constant apply to diatomite as well. The air content of diatomite which makes it light for its volume (i.e. low density) is because it is quite porous. This air content gives it the qualities of being a good insulator much like the old fashioned Thermos flasks.
Also, the water absorption qualities of diatomite also gives it the favourable insulation qualities. This also applies to akadama. See as the water evaporates in the persence of warm weather, it evaporates and takes heat with it (Latent heat of evaporation). It's the same process how sweating cools the body. I use diatomite a lot more these days and with the warm weather up in Townsville, I see it's benefits quite clearly.It's great during the dry weather in being able to rewet easily but drains well during the Wet.
Why pumice is a poorer insulator is because it usually is composed of a glass-like silicate material. There are various forms of pumice, but they are all composed of various forms of this silicate. Unfortunately, this silicate material heats up easily hence it's a poor insulator against heat in bonsai pots.
But what about diatomite? Isn't it composed of 90% silica! That's pretty close to silicate isn't it? Hmmm not really. It's like the difference between coal and diamonds. Both are essentially carbon but in different forms - very different properties. (If you don't believe me, try presenting your significant other with a coal solitaire ring vs a diamond ring - you'll probably get very different responses despite the current high price of coal on the commodities market). Diatomite seems to absorb less heat than pumice.
So in summary, diatomite is porous like akadama. It has similar temperature insulating properties. Unlike akadama though, diatomite doesn't break down over time. The only thing I am personally not clear on is the cation exchange ratio (CEC) of akadama vs diatomite. I suspect they are both quite low.
Whether the Japanese would use it is another question. The Japanese are sticklers for tradition,but there was a time before akadama after all. The Japanese would have migrated to akadama when they realised it's benefits. Maybe the same would occur if diatomite was available to them.
I don't mean to offend by posting this alternative view. That's not my point. All I wish is that, information posted on forums try a stay as factually correct as possible so everyone benefits. The information generally posted on Ausbonsai I think is more accurate than compared with other forums I visit and I think that is an important quality.
If anyone has an alternative view and disagrees with what I've posted above, please speak up. I'm always trying to improve my scientific understanding of what we do in bonsai.
I don't mean to offend but the ability to keep pot temps even is not confined to akadama. See, I agree with what you are saying with regards to the importance of keep pot temps constant and even. But, diatomite is porous like akadama.
Diatomite is inherently porous. That's why it's used in filter media and as an absorbant in spill kits.It's porous like a sponge. At one point in my life, I even was trained to use as Fuller's earth (basically ground up diatomite) to absorb chemical warfare agent on personal clothing and equipment.
Thus all the properties that akadama has in terms of keep pot temps even and constant apply to diatomite as well. The air content of diatomite which makes it light for its volume (i.e. low density) is because it is quite porous. This air content gives it the qualities of being a good insulator much like the old fashioned Thermos flasks.
Also, the water absorption qualities of diatomite also gives it the favourable insulation qualities. This also applies to akadama. See as the water evaporates in the persence of warm weather, it evaporates and takes heat with it (Latent heat of evaporation). It's the same process how sweating cools the body. I use diatomite a lot more these days and with the warm weather up in Townsville, I see it's benefits quite clearly.It's great during the dry weather in being able to rewet easily but drains well during the Wet.
Why pumice is a poorer insulator is because it usually is composed of a glass-like silicate material. There are various forms of pumice, but they are all composed of various forms of this silicate. Unfortunately, this silicate material heats up easily hence it's a poor insulator against heat in bonsai pots.
But what about diatomite? Isn't it composed of 90% silica! That's pretty close to silicate isn't it? Hmmm not really. It's like the difference between coal and diamonds. Both are essentially carbon but in different forms - very different properties. (If you don't believe me, try presenting your significant other with a coal solitaire ring vs a diamond ring - you'll probably get very different responses despite the current high price of coal on the commodities market). Diatomite seems to absorb less heat than pumice.
So in summary, diatomite is porous like akadama. It has similar temperature insulating properties. Unlike akadama though, diatomite doesn't break down over time. The only thing I am personally not clear on is the cation exchange ratio (CEC) of akadama vs diatomite. I suspect they are both quite low.
Whether the Japanese would use it is another question. The Japanese are sticklers for tradition,but there was a time before akadama after all. The Japanese would have migrated to akadama when they realised it's benefits. Maybe the same would occur if diatomite was available to them.
I don't mean to offend by posting this alternative view. That's not my point. All I wish is that, information posted on forums try a stay as factually correct as possible so everyone benefits. The information generally posted on Ausbonsai I think is more accurate than compared with other forums I visit and I think that is an important quality.
If anyone has an alternative view and disagrees with what I've posted above, please speak up. I'm always trying to improve my scientific understanding of what we do in bonsai.
I have used it, but it did not suit me.
There must be something there?
is that wrong 
in a soil that is less than 7 . Both mt silvia and Maidenwell diatomites contain clay contaminants that because of cation exchange properties that make a mixture of silica and clay more acidic. However, because of the small amount of clay relative to silica pHs should be only a little less than 6.0. Because the Mt Silvia diatomite contains more CaO and MgO (alkalis) you would predict it would have a higher pH than the MW diatomite, but not a lot because of the higher silica content.