I use just normal black top soil in my planted tanks. You will want to cap it off with twice the amount of sand (I use rinsed playground sand from home depot, cheapest option).
nah as long as the capping layer isn’t thin, the access nutrients won’t get out and pollute the water. for better results in a planted tank, I would recommend mixing you soil with worm castings, then capping all that with sand. You can cap it with gravel but I’ve never trusted it because it leeches nutrients quicker, sand is just more reliable .
As long as it’s an organic potting soil and doesn’t contain fertilizer/other mainstream chemicals added you should be good! It’s the ferts/chemicals in non-organoc soil that can leach and harm fish mostly.
But otherwise a thick cap layer and you should be good!
SamBeanEsquire 
I use just normal black top soil in my planted tanks. You will want to cap it off with twice the amount of sand (I use rinsed playground sand from home depot, cheapest option).
nah as long as the capping layer isn’t thin, the access nutrients won’t get out and pollute the water. for better results in a planted tank, I would recommend mixing you soil with worm castings, then capping all that with sand. You can cap it with gravel but I’ve never trusted it because it leeches nutrients quicker, sand is just more reliable .
You can try Walstad method – [https://buceplant.com/blogs/aquascaping-guides-and-tips/the-walstad-method-tank-guide](https://buceplant.com/blogs/aquascaping-guides-and-tips/the-walstad-method-tank-guide)
But seems like you are trying to do things fast, so stick to inert….
As long as it’s an organic potting soil and doesn’t contain fertilizer/other mainstream chemicals added you should be good! It’s the ferts/chemicals in non-organoc soil that can leach and harm fish mostly.
But otherwise a thick cap layer and you should be good!