I've used both Fluorite and Eco-Complete substrates in my planted tanks, and I have to say that I prefer Fluorite. While both substrates are similar in terms of their composition and nutrient content, I find that Fluorite has a more consistent size, which makes it easier to work with.
In terms of pros and cons, I would say that Eco-Complete has the advantage of being pre-dosed with liquid nutrients, which can be beneficial for plants. However, Fluorite allows for more flexibility in terms of color options, as it comes in different variations like red, black, and brown.
Ultimately, the decision between Fluorite and Eco-Complete comes down to personal preference. If you prefer a more uniform substrate and don't mind dosing your tank with additional nutrients, then Fluorite might be the better option for you. On the other hand, if you prefer the convenience of a pre-dosed substrate and are satisfied with the color options available, then Eco-Complete could be the right choice.
Remember, there is no right or wrong answer here. It all depends on what works best for your specific tank setup and aesthetic preferences. Happy planting!