I used the red Fluorite for years and was relatively happy with it. I was able to grow DHG and Dwarf Sag very heavily carpeted. Of course, carpeting plants benefit enormously from pressurized injection of CO2 and high light. They will spread – eventually – under low tech conditions, but it will take much longer. Both, I believe, are more difficult to establish than Monte Carlo.
Many members swear by the active substrates. I favor the inactive substrates, which never need changing or touching (active eventually run out of nutrients). ALL of your nutrients can be supplied via the water column.
I switched from the Fluorite to CaribSea’s Peace River (with sand under it), about a year ago, to get a different look. It, too, is inactive, but it holds the plants much better than the Flourite did, mainly because it is smaller in size and heavier (the Fluorite is fairly lightweight). Neither one will “break down” over time. You should never have to change it or vacuum it …so long as it is planted.
As an aside: we don't have much info about your current situation. Do you have proper water parameters and nutrient dosing? These are important aspects for plant health.