If concentrated Prawn poo-poo and water is considered an organic pollutant then this should do the trick….

Ultrathin Covalent Organic Framework Anchored on Graphene for Enhanced Organic Pollutant Removal.

Just target the poo-poo profile…which can only be a factor of inputs and metabolism.

https://onlinelibrary.wiley.com/doi/10.1002/anie.202206564

Check out Prawn Nitrite “Colorimetric Titration” App…

https://play.google.com/store/apps/details?id=es.inforapps.chameleon