Fluval Stratum vs ADA Aqua Soil
My experience with plant substrates is limited, but I have used both Fluval Stratum and ADA Aqua Soil (normal type). I found AS to be a much better product.
I first used it in my 50g planted tank, after having used FS. After a few short months the FS was breaking down and becoming that dreaded "sludge" that these kinds of substrate tend to turn into. So I added a 3L bag of AS to the FS and found that after about the same amount of time, the AS was not breaking down like the FS. Not only was AS longer lasting, but the plants responded quite incredibly, growing much better than before with just FS.
The second time I used AS was in my 2g planted tank. I experienced the same as before, long lasting and exceptionally fertile substrate. My plants grew quicker in just a AS substrate system, rather than my previous mixture of FS and AS. This confirmed my conclusion that AS was/is a better substrate.
Moving forward, I plan on using AS as my "go-to" substrate. Although I have an unopened bag of Red Sea Flora Base. I do not know how it compares to AS, but from what I have read it is one of the few substrates that come close to AS in terms of quality and performance, unfortunately to my understanding, Red Sea has discontinued this product.