We bought snails to go in the frog tank to eat the frog poop. So now we have a perfect system. Crickets feed frogs. Frogs poop. Snails proliferate. Extra snails go back to pet store in exchange for more crickets. It's not often things work out that neatly.
An aside: early in the morning, since the weather has (finally) become more warm, the frogs make a sound I can only describe as barking. Is that normal?