Guys, sorry to be vague. It's exactly as stated by squid102.
The fact of the mater is just that Akadama, or Kyushu, or Capetown, or Zambeze, or even Congo, or WHATEVER are all just different forms of dirt.
But guess what? Weeds are found almost exclusively growing in dirt. So there is no problem using any of this stuff if you can live with the annoyances or disadvantage of each. The plants don't really care, as long as nutrients are made available to them.
If you dose the water column regularly, then this is sufficient. If you choose to use a more professional dirt then you can pony up the cash for an enhanced, nutrient fortified dirt such as ADA Amazonia. It's got NPK, trace elements and peat baked on the clay particles. So it's loaded with nutrients and plants will make excellent progress. Akadama is just a nutrient poor version ADA Amazonia. They are both clay dirt. The Amazonia is also baked so it's a bit tougher than Akadama and therefore does not cloud up as much. It's an outstanding dirt, but it's just dirt.....and it costs a LOT, so every dirt you choose will have an advantage and disadvantage from an ergonomic, economic, maintenance, aesthetic, and mechanical point of view. However, do not be hypnotized by marketing tactics, but instead look at them with eyes wide open.
Your choice of substrate, in-and-of-itself, will not matter as long as you address the shortcomings of each. If you have a nutrient poor substrate like Akadama you can fortify it with nutrients by lining the bottom of the tank with some gains of Osmocote or other branded slow release fertilizer. You must be sue to have it at the bottom of the substrate because it releases ammonia, so you don't want to have it near the top where it will diffuse into the water column where the fish are. This also can be done very cheaply and it can be almost as effective as Amazonia.
You can also use plain sand, and even fake gravel from the LFS. You just have to ensure that the water column is dose regularly with NPK+Traces. You can put little bits of peat or any organic matter like rotted leaves. Some of these products are sold on the market, but they have fancy sophisticated name, like "Orion's Belt" or "Transformer", so we think they are some kind of laboratory invention, but they are just like Dust in The Wind (see: Kansas).
So, use them, or don't use them. If you follow our Standard Operating Procedure (SOP) then your plants will not care.
See
Flora max V Eco complete | UK Aquatic Plant Society for more info.
Cheers,
