XP Deus II Underwater & Saltwater Masterclass: Fine-Tuning FMF Settings, Salt Sensitivity & Deep Target Behavior

[The Lost Ring]

Hi everyone,

Looking through the XP Deus forum, I’ve noticed that most discussions heavily focus on land hunting, relic hunting, and inland coin shooting. While the Deus II is undoubtedly an absolute beast on land, I want to start a dedicated, long-term thread focusing specifically on underwater, salt water diving, and wet sand hunting.

Recently, while diving and fine-tuning my custom underwater program (based on program 12 / DIVING), I encountered some interesting technical nuances regarding stability, conductivity, and target response in salt water that I think are worth discussing.

Here are a few key points and observations I’d love to get your thoughts and experiences on:

The "Salt Noise" vs. High Sensitivity Dilemma:
Running sensitivity around 85–90 in high-salinity water often leads to chatter/falsing. In my tests, the breakthrough was balancing Salt Sens and Max Frequency. Bringing Salt Sensitivity up to 8 - 9 and lowering/adjusting the frequency range drastically eliminated chatter without sacrificing depth on small/medium gold rings. What are your sweet-spot values for Salt Sens in heavy salt environments?

VDI Shift on Deep Gold (Cartier/18K Case Study):
We often associate VDI values in the 45–56 range with pull-tabs or aluminum foil on land. However, underwater—due to salt conductivity, depth (10–15 cm+), and target geometry—small or mid-sized 18K (750) gold items frequently drop straight into this 45–56 VDI window. A great reminder that if we discriminate above 30 or skip "aluminum-like" signals underwater, we pass right over high-end gold jewellery!

Wired Underwater Headphones (BH-01 / Bone Conduction) Behavior:
For underwater use, when plugging in wired headphones, the unit automatically routes audio via the rear socket while remaining in the SPEAKER profile. Trying to switch to wireless headphone profiles (with the wave icons) can cause confusion. Keeping it straightforward on Speaker mode lets the physical connection take over effortlessly.

Ground Balance (GB) & Magnetic Setting:
In salt water, setting Magnetic Ground to "Accept" and utilizing Ground Tracking in Salt/Beach mode made a huge difference in taming sudden signal pops.

I’d love to hear from other divers and beach hunters using the Deus II underwater. What program base are you running? What are your exact settings for Reactivity, Audio Response, and Disc in your local waters?

Let’s turn this thread into a comprehensive reference guide for all Deus II underwater hunters!

 

[RichW]

Hi everyone,

Looking through the XP Deus forum, I’ve noticed that most discussions heavily focus on land hunting, relic hunting, and inland coin shooting. While the Deus II is undoubtedly an absolute beast on land, I want to start a dedicated, long-term thread focusing specifically on underwater, salt water diving, and wet sand hunting.

Recently, while diving and fine-tuning my custom underwater program (based on program 12 / DIVING), I encountered some interesting technical nuances regarding stability, conductivity, and target response in salt water that I think are worth discussing.

Here are a few key points and observations I’d love to get your thoughts and experiences on:

The "Salt Noise" vs. High Sensitivity Dilemma:
Running sensitivity around 85–90 in high-salinity water often leads to chatter/falsing. In my tests, the breakthrough was balancing Salt Sens and Max Frequency. Bringing Salt Sensitivity up to 8 - 9 and lowering/adjusting the frequency range drastically eliminated chatter without sacrificing depth on small/medium gold rings. What are your sweet-spot values for Salt Sens in heavy salt environments?

VDI Shift on Deep Gold (Cartier/18K Case Study):
We often associate VDI values in the 45–56 range with pull-tabs or aluminum foil on land. However, underwater—due to salt conductivity, depth (10–15 cm+), and target geometry—small or mid-sized 18K (750) gold items frequently drop straight into this 45–56 VDI window. A great reminder that if we discriminate above 30 or skip "aluminum-like" signals underwater, we pass right over high-end gold jewellery!

Wired Underwater Headphones (BH-01 / Bone Conduction) Behavior:
For underwater use, when plugging in wired headphones, the unit automatically routes audio via the rear socket while remaining in the SPEAKER profile. Trying to switch to wireless headphone profiles (with the wave icons) can cause confusion. Keeping it straightforward on Speaker mode lets the physical connection take over effortlessly.

Ground Balance (GB) & Magnetic Setting:
In salt water, setting Magnetic Ground to "Accept" and utilizing Ground Tracking in Salt/Beach mode made a huge difference in taming sudden signal pops.

I’d love to hear from other divers and beach hunters using the Deus II underwater. What program base are you running? What are your exact settings for Reactivity, Audio Response, and Disc in your local waters?

Let’s turn this thread into a comprehensive reference guide for all Deus II underwater hunters!

I don't dive but I wade fairly deep in salt water frequently. I run the D2 antenna to the remote with enough slack to allow me to put the remote in my top shirt pocket. I can still use my wireless headphones (which I love) and hunt chest deep on most days. If it's really rough I grab another machine that day. The Diving program definitely is the most stable in the salt water with max frequency at 14 kHz . Any max frequency greater than that the unit begins to get pretty noisy and depth begins to taper off. I do try to keep salt sensitivity around 8-9 and still dig a lot of small foil with 14 Khz max setting. I'm going to have to try the magnetic ground accept and ground tracking set up. I think the machine runs great on the wet and dry beaches , relic sites and parks. But when I take it into the salt water I'm not all that impressed. I also felt the same way when I tried the Equinox. I have not tried a Manticore . Maybe it's different. I'm comparing the depth to older water machines. I have a pretty hot CZ-21 which gets better depth on everything but the smallest targets. I also use the Original Fisher Impulse with 8" coil and it gets incredible depth. None of the newer machines can get close to it in salt water. After a few hours with it I can barely make it back to my car. I'm going to try some of your settings on the D2 and hope for improvement Thanks for starting a great discussion.

 

[The Lost Ring]

I don't dive but I wade fairly deep in salt water frequently. I run the D2 antenna to the remote with enough slack to allow me to put the remote in my top shirt pocket. I can still use my wireless headphones (which I love) and hunt chest deep on most days. If it's really rough I grab another machine that day. The Diving program definitely is the most stable in the salt water with max frequency at 14 kHz . Any max frequency greater than that the unit begins to get pretty noisy and depth begins to taper off. I do try to keep salt sensitivity around 8-9 and still dig a lot of small foil with 14 Khz max setting. I'm going to have to try the magnetic ground accept and ground tracking set up. I think the machine runs great on the wet and dry beaches , relic sites and parks. But when I take it into the salt water I'm not all that impressed. I also felt the same way when I tried the Equinox. I have not tried a Manticore . Maybe it's different. I'm comparing the depth to older water machines. I have a pretty hot CZ-21 which gets better depth on everything but the smallest targets. I also use the Original Fisher Impulse with 8" coil and it gets incredible depth. None of the newer machines can get close to it in salt water. After a few hours with it I can barely make it back to my car. I'm going to try some of your settings on the D2 and hope for improvement Thanks for starting a great discussion.

Thanks for the feedback!

You’re totally right about the raw depth of PI machines like the Impulse or CZ-21 in salt water. If you don't mind the weight and no target ID, a solid Pulse circuit will punch through saltwater depth all day long. For me, the D2's big advantage is just the weight and target unmasking—much easier on the body after a few hours underwater.

Out of curiosity, what coil size are you running for your saltwater wading? The 9", 11", or the 13x11"? I’ve noticed coil size plays a pretty big role here—not just with water resistance when sweeping, but also in how much saltwater matrix the FMF algorithm has to handle at one time.

Since you're chest-deep with the antenna running up to your pocket:
Definitely try the Magnetic Ground (Accept) + Ground Tracking combo next time out. It really helps tame those false pops when the coil distance shifts over moving sand and waves.
If you want a bit more depth at that 14 kHz max frequency limit, try dropping Reactivity down to 0.5 or 1 (assuming the area isn't carpeted in trash). It gives the Multi-IQ processing just a split second more time on target, which helps pull up those deeper, whisper signals.
Let me know how the GB setup works out for you next time you're in the water, and curious to hear which coil you're swinging!

 

[RichW]

Thanks for the feedback!

You’re totally right about the raw depth of PI machines like the Impulse or CZ-21 in salt water. If you don't mind the weight and no target ID, a solid Pulse circuit will punch through saltwater depth all day long. For me, the D2's big advantage is just the weight and target unmasking—much easier on the body after a few hours underwater.

Out of curiosity, what coil size are you running for your saltwater wading? The 9", 11", or the 13x11"? I’ve noticed coil size plays a pretty big role here—not just with water resistance when sweeping, but also in how much saltwater matrix the FMF algorithm has to handle at one time.

Since you're chest-deep with the antenna running up to your pocket:
Definitely try the Magnetic Ground (Accept) + Ground Tracking combo next time out. It really helps tame those false pops when the coil distance shifts over moving sand and waves.
If you want a bit more depth at that 14 kHz max frequency limit, try dropping Reactivity down to 0.5 or 1 (assuming the area isn't carpeted in trash). It gives the Multi-IQ processing just a split second more time on target, which helps pull up those deeper, whisper signals.
Let me know how the GB setup works out for you next time you're in the water, and curious to hear which coil you're swinging!

I'm running the 9" coil. I never run the reactivity higher than 1.5 in the water and I do use .5 or 1 most of the time . I hip mount both the CZ-21 and the Impulse. If I couldn't hip mount them I would never use them. Appreciate the advice.