Bob A wrote:

I have 1/3 fluorite substrate, Phyl says after 3 months start using Flourish
tabs in the substrate.

I love Phyllis, I have sent her two customers this month alone, and the plants
she sold them were, as always, spectacular. Right now she is shipping Madagascar
Lace plants that are to die for.

But Phyllis keeps recommending mixing Flourite with gravel to help hold the
plants down. Since I've never had a single plant not stay down in my 100%
Flourite substrate, I don't understand this recommendation.

Since it holds down plants just fine, the only reasons to mix it are cost or
looks. If you decide to mix, remember two things:

1. The Flourite bag recommends not using less than 50% Flourite.

2. Unless the gravel is a similar size and shape, the mix will separate over
time. Sand will separate to the bottom, being more dense and smaller, as will
smaller pebbles. Larger gravel could go either way depending on size and shape,
but usually down.