Put a sponge on your canister intake.
I combined the dirt with the Turface, which is just calcined clay, for the cation exchange properties that the clay offers. The dirt I used was just my local, outside topsoil which is very good stuff. Lots of people use the Miracle Grow organic, which works great, but has a lot of organic matter in it (surprise surprise) that will mean a large ammonia spike. The trick is lots of plants to start with, which means a big expense for a tank that size. Has to be done though. You want lots of floaters to begin with, like water lettuce, and Hornwort - nutrient sponges they are.
If you do research you'll find a lot of stuff about mineralizing the topsoil before you use it - ignore it if you wish. A huge effort, and not at all necessary. You're red clay is actually a good thing - I'd mix that in with your purchased soil if you go the dirt route - your clay has iron in it - that's good. I put clay balls in my soil mix.