kH seasonal cycles?

I have read numerous threads regarding kH/pH and their interrelations.
That is not what I am interested in.

What I would like to know is:
has anyone intentionally altered their kH, trying to simulate natural
'seasons'(rain, drought cycles)?
if so what is the kH range that you work with?
results?

I have been experimenting with this idea on one tank for 2 1/2 years,
using sodium bicarb to influence kH levels

range: 18ppm (7months) 38ppm (5months) of course the change is gradual
(takes roughly 4 weeks for the 20ppm change) pH remained relatively
stable 6.6 - 7.0

results: I found almost all species in that tank went into a breeding
cycle. guppies (bad example - those little sex fiends), clown loaches,
gouramies(true honey), neon tetras. All seemed to produce eggs -
except the guppies(live bearers) - with viable offspring. Unfortunately
I also have a host of short-finned spiny eels in that tank, making fry
fair game as food.

While these results are by no means 'scientific' or representing the
absolute truth. I will continue experimenting and combine any input
that is provided.

Another question
Can anyone think of reasons not to do something of this nature?
backing?

Kris