I'm looking into the next step of building my 36 gallon: Substrate and decor. I was doing some research since it has been so long since I bought substrate. In my research I came across some ideas that certain substrate can leak ammonia?! Now I'm concerned and unsure on the best substrate for my future planted tank. And am unsure if the substrate I've had in my 20 gallon could cause potential problems in the future. I was thinking Flourite which is what is in my 20 gallon. A mixture of their clay and sand substrate. Any suggestions or advice to ease my mind would be greatly appreciated.