You must remove the poop when you notice the odor or see poop. This will reduce the odor. earthworms cause their poop to smell bad, but that is normal. You just have to make sure you remove the poop right away. If you smell anything give your frog a Luke warm de-chlorinated soak while you check the frogs hole. Remove the substrate where the hole is if necessary. After performing this task toss the substrate(mix it up) mist it and then remake your frogs hole. The frog will return to its burrow that you reformed and the odor should be reduced.

if you want you can buy some that Zoo Med Eco Carpet and place it in the tank and place the substrate over it. This will help and also keep your frog from sitting in it urine. I do this and never have terrible smells at all after the feces are removed.

Always make sure you remove the feces immediately.