HI 9147 is designed for aquaculture applications. This unit is unique among DO meters as it is supplied with a galvanic probe. Unlike polarographic probes, galvanic DO probes require no conditioning time. When you need to measure multiple samples in a given period of time, pick it up and measure on demand. HI 9147 is a must have for DO sensitive organisms or high bio-load environments...like your aquaponic system!