I’m also interested in Nitrate sensors. I’m a HS teacher and have a grant to install a greenhouse. I am wanting to set up an aquaponics system to grow starts for an area we are reclaiming into native grasslands, a a rain garden, and pollinator garden we have started at my school. I’d love to get some nutrient monitoring for the water quality of the system for my own management of the system and also for my students to work with. I see temp, turbidity, and salinity monitors very standard, but I would also really like Nitrate and Ammonia monitors.