HYDROP is only compatible with COROS NOMAD, VERTIX 2, and VERTIX 2S. It is not compatible with other watch models or brands.
Once your HYDROP is set up and paired with your COROS watch, you're ready to cast it and start measuring the water environment around you.
Attaching HYDROP to Your Fishing Rod
Use one of the included eyelets in the packaging to connect HYDROP to a weight, as illustrated below:
It's recommended to use a line with a lower tensile strength than your main line to connect the weight, to reduce the risk of loss if snagged.
Initiating a HYDROP Measurement
There are two ways to start measuring the water with HYDROP.
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In Standby mode (without tracking a Fishing activity)
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On your watch, press and hold the Back button to open the Toolbox menu, and scroll to HYDROP. (The HYDROP widget and the Fishing detection screen are only visible if a HYDROP is connected to your watch.)
- Select your HYDROP device and wait for a successful connection. Press the dial to start measuring.
- When connected, your watch will display this prompt: "Please cast the HYDROP into the water."
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While recording a Fishing activity
- Start tracking any Fishing mode on your COROS watch.
- Press the Action button (lower left button) to enter the HYDROP screen. (This screen is only available if a HYDROP is actively connected.)
- Select your HYDROP device and wait for a successful connection. Press the dial to start the measurement.
- When connected, your watch will display this prompt: "Please cast the HYDROP into the water."
Taking a HYDROP Measurement
Cast the HYDROP into the water. Wait for it to sink to the bottom, then begin retrieving at a steady speed until it exits the water. A timer will begin tracking the retrieval time on your watch screen. For best results, it's recommend to retrieve HYDROP at a slow and steady pace, taking about 1 to 1.5 minutes for the retrieval process.
During retrieval, press the Back button on your watch if you wish to cancel the measurement.
After HYDROP exits the water, it will automatically reconnect to the watch and transmit data. After transmission, you will be prompted to enter the casting distance. Select the distance on your watch or choose to skip, and then the HYDROP measurement results will be displayed on your watch screen.
Taking Another Measurement: You can start a new measurement via the HYDROP widget in the Toolbox menu, or within a fishing mode. After a measurement is complete and the chart is displayed, you can perform another measurement by pressing the Back button to return to the initial connection page and then initiate the measurement process again. A new chart will display automatically when HYDROP exits the water. If HYDROP is cast back into the water while data from the previous scan is still transmitting, you will see: "Transmission interrupted. Please reconnect to complete transmission," with an option to abandon the transmission.
Understanding Data from HYDROP
On your watch, scroll down from the HYDROP status screen to view past records. (You can access the HYDROP screen by pressing the Action button.) This summary screen will automatically load after each measurement. While viewing the summary page for a measurement, you can scroll down to view light intensity and water color data. Or press the dial to enter the detailed view, where you can scroll or swipe to view depth, temperature, and more.
- Water Depth: HYDROP can measure water depth between 20 cm - 40 m.
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Temperature by depth: HYDROP tracks water temperature vertically as it moves through the depths, helping you find that "golden" layer of water where the fish are actually active and feeding. The temperature curve in the graph uses 0, 8, 15, and 25°C as critical thresholds, dividing it into four color segments. Each point on the curve represents a temperature value. A light green indicates warmer temperature, while dark blue indicates colder temperature.
- The top layer of the water, called the epilimnion (or temperature jump layer), is the warmest. Because warm water is lighter, this layer is less dense and moves easily when the wind blows. Wind also helps mix oxygen into this layer, so it has plenty of oxygen and plant life, and most game fish prefer this layer.
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The middle layer is called the thermocline (also known as the metalimnion). In this zone, the water temperature drops quickly as you go deeper. Many schooling fish gather here because the light levels and cooler temperatures create an ideal environment for them.
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Water Color by depth: Using optical sensors, HYDROP measures transparency and identifies the water's true color profile. It tells you exactly how much light is penetrating the depths so you can pick the lure color and lure size that will actually pop.
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Light Intensity by depth: Underwater brightness helps you find the right color for your lure and also adapt his shape (shad tail, finless, etc.) to what the fish see. Some lure colors are more visible in darkness, and others are more visible when it's bright. Light Intensity is divided into 6 measurements, from the Darkest (0) to the Clearest (5).