So I set up a 10 gallon Fire Belly Toad tank, but I think I might have messed up on the substrate.

The only thing I could find was Peat Moss...I read from multiple sources that it would be just fine with fire bellies...but just recently Iv ALSO read that it could cause impaction..
Not to mention it holds almost NO water at all....So watering my plants is getting complicated.

Did I mess up on substrate?
If I did, am I able to just cover the top layer with a new substrate to avoid impaction?
Or will I have to start over? The fire bellies JUST went in today...I don't wanna over stress them or something.