Cinnamon won't hurt...not sure how much it'll help, either.
I've used it to prevent rot on succulent cuttings and to treat cases of root-rot - in those cases, it was quite effective and never harmed my plants. Anyhow, go ahead and give it a try. I also recommend that you elevate the container - even just an inch or two - and be sure to flush the mix again soon. Terro ant poison works wonders :-)

Also, once you actually have your maple in the Gritty Mix, the fungus gnats will cease to be a problem.

Josh

I would look for the reason for the ants being attracted to your maples. Do the maples show any sign of aphids or scale, which would produce honey dew and feed the ants? Al

Nope no honey dew. I have hollys around my house and def know what honey dew looks like. I did have the pots on the ground. I just recently got them up off the ground. They are the little ants. Could they be attracted to my fertilizer Dyno gro?

No, they're not attracted to the fertilizer.
They just like to take up residence in pots...and farm aphids, most of the time.

Josh