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Isolite and ADA substrates

Someone asked about a calcined clay product called "Isolite" recently and
wondered about it's use in a substrate. I found a link on the Bonsai Web to
a supplier of this material and sent them an e-mail query. It would appear
that Isolite is a "formed" or "extruded" material which is kiln fired, so it
will hold both it's shape and form when wet (it shouldn't get mushy like
kitty litter). It "looks" similar to rabbit feed. Isolite contains internal
pore spaces which are larger than 1 micron in size, making the material
(according to the information I received) ideal as a host surface for
bacterial filtration. To support this contention, they state that 1 cubic
foot of gravel has approximately 150 sq ft of surface area, 1 cubic foot of
sand contains about 1,500 sq ft of surface area, and Isolite, due to it's
internal pore structure, has a surface area of almost 700,000 sq. ft. per
cubic foot of material.

Isolite is sold in a number of different granular sizes, 1 mm, 2 mm, 4mm,
6mm and 10 mm.

The material is quite pricey - depending upon the quantity you order it
ranges from a high of $3.39 per lb. down to $1.50 per lb. Shipping and
handling is included in their pricing (except of course for those of us who
live in Canada - we get hit with an extra charge of $15.00 per order).

Seems that the cost of Flourite isn't so bad after all...

Guang Yan Wang was asking about ADA substrates and Christopher Coleman
provided some information.

> The ADA substrate is 2 part:  The bottom layer is a pumice stone
> mixed in with peat called "PowerSand" whose purpose is to regulate
> to some extent the pH.  The top layer is a baked clay called "AquaSoil"
> with neutral effect on pH. Both substrances are quite porous,  which
> provide for good bacterial growth.

According to information which I received from Hideki Higuchi, who is with
ADA in Japan, Aqua Soil does have an effect on both the Hardness of the
water and on it's pH.

"POWER SAND SPECIAL is richer in organic matters and does also contain a
certain amount of BACTER 100 and CLEAR SUPER. It is designed to feed
Echinodorus or Cryptocorynes. For an aquarium with kinds of plants which do
not require much nutrients in the substrate, the plain POWER SAND (plus
BACTER 100 and CLEAR SUPER) is recommendable for excessive nutrients may
increase the risk of algae appearance."

Concerning the differences between the three varieties of Aqua soil which
ADA sells, Mr. Higuchi had this to say (I had commented on Aqua Soil's
ability to reduce Hardness and pH, and wondered if there was any difference
in the degree of this effect among the various varieties of Aqua Soil):

"The difference among the three types are only the color and the "touch".
You can choose any type simply according to your preference. Any of the
three gives the same benefit to the water."

"Based on our experience in Japan : Our local tap water has a TH value
around 50-60 mg/l. In a 60 lit. aquarium with AQUA SOIL, the TH value goes
down to 20 mg/l within a week. Generally speaking this is the desirable

So it would appear that the presence of peat in both Power Sand and Aqua
Soil is going to affect both the total Hardness and the pH of the water. As
Christopher noted however, the presence of peat or any other pH modifying
agent _other_ than the bicarbonate buffer system will make the use of the
popular CO2-pH-KH table difficult, if not impossible.

from Christopher's post:

> One of the issues I have with any peat based product is that is  _does_
> manipulate pH.  I think one of the main focal points of successful planted
> tank is CO2 and one of the most important CO2 reference materials we
> have is a table - available on this list - which determines CO2
> levels as a
> funtion of KH level and pH level.  But the charts accuracy is compromised
> when the KH comes from sources other than popular bicarbonate sources
> (calcium carbonate, sodium bicarbonate).

I believe that ADA acknowledges this, for in Aqua Journal v34, in an article
on CO2 fertilization they make mention of the fact that they recommend the
use of their "Drop Checker" which uses a pH indicator fluid (Dupla and Eheim
also have similar devices which I assume work using the same principles).
They _claim_ that this is a more accurate method of determining CO2

As I'm no chemist, but there _are_ a number of very knowledgeable chemists
on the APD, could someone make a comment on this issue? Peat has been used
in aquarium, both planted and otherwise, for years. An excess of tannins and
other material which will leach from peat _can_ be harmful to plant growth
but moderate amounts certainly are not (not in _my_ experience anyway).

What is the difference in accuracy between, for example, a LaMotte CO2 test
(properly sampled and titrated) and the CO2 concentration read off of the
"CO2 Chart" which Dupla first introduced? Both in tanks which are only
buffered using the bicarbonate system and in those which might contain other
modifiers? Just how important _is_ that table (especially as it is based on
KH and not on Alkalinity)? Can we not depend upon the reading from a LaMotte
CO2 test?

As an aside, I have one of ADA's Drop Checker's (got it from M3) and while
it is certainly a thing of beauty, it is _very_ difficult to read due to the
fact that it is totally transparent (the Dupla CO2 monitor has a white
background which shows the color change of the indicator fluid much better
in a tank with a dark backgound.

James Purchase