The western type (sodium ) swells more, than the calcium type does.
The western type leaves a slimey residue inside pipes and filter
boxes, which usually winds up attrating more junk that adheres in the
pipes etc.

The western type being more absorptive leads to clumping in some some
systems as it is moved through the filter boxes and such, where ther
calcium type does not have this problem.

You hear folks say the fish can utilize the properties of calcium
better than that of sodium, which I can not say if they do nor not,
but there is all kinds of claims to this being the case........All
koi clays I have seen or read about are all calcium based.....While I
do not use koi clay to treat my pond, my pond has a heap of bentonite
of both types in it, both from ignorance in use and for sealing
seeps.....The western bentonite is good at sealing up seeps and leaks
where the calcium is not.......They mine southern bentonite a few
miles from where I live, and I can get tons of it for free as long as
I care to shovel it up out of the warehouse where its bagged and
processed.......

I use both types in my foundry with calcium being the most used, but
thats neither here or there in regards to ponds.

I have heard some real horror stories of folks that used western type
with clogged filters, pump inpellers getting coated up and pump
efficiency reduced, and it seems to be more pronounced if they used
pelleted or granular form as compared to milled mesh sizes of 400 or
finer.......I can only assume the western would clump up too quick
once it hits the water, whereas the calcium would not....all due to
the differences in the two types. I know when I broadcast sodium over
a seep, it will float, and when its particles touch each other, they
knit together, eventually making a floating mat, until they absorb
sufficient water and eventually sink. The calcium floats as well, but
does not form into larger ever growing globs of clay. The granular
and pelleted type sinks rather rapidly, but just swells up and
continues to gather more and more bentonite and other debri in the
process, whereas the calcium seems to dissapate throughout the water
column.

So like I stated, I have no actual experieince with it used for making
water clearer etc, as I never used it for such......but my natural
pond which contains both has very good looking water....BARAClear P-80
uses calcium bentonite as a binder and buffer, to aide in clearing
water of algae and reduce turbidity. Baraclear is made by one of
Bentonite Corp numerous smaller concerns, and since Bentonite Corp,
is the worlds largest producer of bentonite products, and handle both
calcium and sodium based clays, there has to be a reason they are
using the calcium clay for reducing turbidity and algae in the
water....I have and continue to use Baraclear, mainly for ther
aluminum sulphate properties in locking up phosphorous content of my
ponds water, so if the calcium has benefitted my koi or not I can't
say......

I can find lots of sodium bentonite here and there in clumps in my
pond if I look close, but it seems the calcium just mixes in and sort
of dissapears. I also found that when I apply sodium when I had a
leak, even my pumps prestrainer and also leaf basket / primer pot got
a pretty heavy buildup of film. It does not get this whenever I added
calcium. I do not filter my pond as its too large and only use
strainers to keep junk out of the pump that I use for aeraton and
powering water features. I have to belive like others have experienced
that using it in a pond with filter media would lead to media that
gets loaded up with kitty litter or western bentonite film and clumps.
Thats one reason well drillers use sodium as it mnakes a heavier
denser clumping slurry than calcium does.....as its geared at sealing
more than disperseing and migrataing freely than calcium is capable
of.


So thats my experiences with bentonites of both types.......
I have to belive that addition of bentonite in a pond with a filter
system is akin to using a floculant in a hot tub, so it can collect
smaller particles into larger masses for filter removal. But you sure
do not want huge globs of accumulated junk migrating through the
system either, which is what you have a good chance of having with
sodium bent.


On Thu, 14 Jul 2005 12:41:43 GMT, " George"
wrote:

===
==="Roy" wrote in message
. net...
===
=== The propertys of the two clays are entirely different.......One will
=== do the job (supposedly) and the other is used by those that don't know
=== any different simply because its bentonite and they considfer
=== bentonite all one and the same, which it is not. i'm not gonna get
=== into a blow by blow difference in clays, as there is a heap of info on
=== the various bentonite clays, with a google search....
===
===Roy. I'm a geologist, and have used both types of bentonites extensively in
===my work. The question still stands. Why do you say that one is preferred
===over the other for use in garden ponds? The are both highly adsorptive,
===and highly hydrophilic, so what difference does it make? Although they're
===chemistry is slightly different, their physical properties are nearly
===identical.
===


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