# Do substrate heating coils fertilize the substrate?

```George wrote:
> George wrote:
> >Duplarit captures nutrients pulled into the substrate by convection
> currents,
> >thus making the substrate appropriately fertile.
>
> Steve refutes this:
> >There are no scientific studies [that he knows of] to prove this,
> therefore it
> >can not be true.

George, you come out with this wild theory that laterite is fertile
because heating cables draw nutrients into the substrate and you have NO
EVIDENCE to substantiate this claim. There is no scientific experimental
evidence. If you knew of any, then we must assume that you would have
trumped it out by now.

If you wish to make a point about the ability of laterite to hold and
capture nutrients in the substrate, then you should perform an analysis
of the AMOUNT of nutrient which laterite is hypothetically capable of
holding.

CEC as we all recall, is cation exchange capacity which measures the
AMOUNT of nutrients in centi-moles per kilogram of material. Given that
200 grams of the stuff in a rather large tank (what's it rated for 70
gallons?) indicates that it can't really hold a lot of nutrients, now
can it? Do the math if you want to justify your hypothesis George. I'll
spare you the further details on the varying affinities of cations;
suffice to say that any rigorous analysis should also take this into
consideration.

On to the subject of convection currents. George again is treading on
the slippery rocks (must be the clay on them) Please do enlighten us
with the quantitative numbers. If you have no experimental values, then
please do feel free to quote Reynolds Numbers and fluid mechanics
formulae at length. Be sure to mention the co-efficient of thermal
expansion of water and the resulting hydrostatic forces. Don't forget to
factor in the viscosity of water and the average path length between
particles.

Let me make one other point _very_ clear. The burden of proof for an
hypothesis is entirely on the proponent. It is NOT up to everyone else
to disprove theories.

Since George summarized me, its fair turn about that I summarize him.

George goes on at length deflecting from the issue that he has made an
unsupported assertion that heating coils are in any way effective at
bringing nutrients into a laterite substrate.

My response ...

Ain't silence golden? ;-)
```