I'm a bit denser than some, but eventually I know that a major pruning
is required when:

* The camera has to be set two f-stops lower than usual to take
a picture of the tank because it is so dark

* It's 2003, and you find a species floating on the surface that
you thought you got rid of in late 2001 (Water sprite).

* You only tied one rhizome of Anubias to your driftwood.
You break off two large rhizomes that had grown on the
back side of the driftwood. Three large rhizomes remain.

* There's a black shrimp hiding in the removed Anubias. You
have never purchased a black shrimp.

* There's Java fern growing in the removed Aunbias. You
took out all the Java Fern 6 months ago.

* There's Baby Tears growing in the removed Java Fern. You
took out all the Baby Tears 3 months ago.

* You cut 37 leaves off two swords, and they still look full.

* You discover two new 8-inch swords behind the large
swords while you are pruning.

This all happened yesterday. At 2pm, I told my wife I needed an hour to
clean the tank, then didn't finish until after dinner. I estimate that I
removed 40-50% of the plant matter in my tank, and it still looks
heavily planted.

I'm hoping this solves the mystery of why the fert dosing that used to
be adequate to promote fast, algae-free growth has recently seemed
inadequate-I had far more plants than I had realized! Tom Barr's latest
recommendations (the Estimative Index) are starting to make a lot of
sense.