safe aquarium deco?

[KMAC]

Any fishless way is best, Long process though when adding food or dead shrimp etc to break down. The vast majority of NH3/4 is actually produced via fishes gills so if you add bacteria at the same time as your fish you will be sorted. Just do more frequent water tests until NH3 & NO2 are at zero then you dont need to test as often. You can work out water changes by monitoring NO3