Hi Slippery bisvuit.
I have use Maidenwell Diatomite in my mix for several years now.
I find it helps hold open the potting mix (bark) as the bark ages, is lightweight and is porous so as to hold a small amount of water.
i use the same size Diatomite as the bark.in the Mix
Below info off thier website at
http://www.maidenwell.com/documents/...enwellmsds.doc “Maidenwell
Diatomite” is a rich source of plant available silica which is widely documented to stimulate Self Acquired Resistance (SAR) in plants thereby increasing their resistance to disease. Maidenwell Diatomite consists of the skeletal remains of microscopic single cell aquatic plants known as diatoms. These small plants developed an opaline silicious shell like armour for protection, upon the death of these plants the fossil shells accumulated on the beds of these fresh water lakes and compacted into lightweight porous rock.
Cheerio
Ron ITS raining outside and my rainwater tank is finally filling.