Garrett AT Pro
Garrett AT Pro Settings by Site Type: Park, Field, Beach and Relic
Quick answer
Start the Garrett AT Pro in Pro mode with sensitivity around three quarters, ground balanced on site. Use Coins mode in trashy parks, Zero or Custom with Iron Audio for relics, and drop sensitivity two or three notches on wet salt sand, where a single frequency machine has a real limit.
Settings are a response to ground, not a personality. The Garrett AT Pro ships with Standard, Zero, Coins and Custom search modes plus a separate Pro mode audio option, and the difference between a productive day and a noisy one is usually three decisions: which mode, how much sensitivity the ground will actually carry, and whether Iron Audio is on.
What follows are starting points to be adjusted in the first ten minutes on site, not settings to be copied and left alone. Every one of them interacts with soil mineralisation, and the honest limit of this machine in salt water is covered below rather than buried.
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Garrett AT Pro
Waterproof to 10 feet with Pro mode proportional audio, which is the setting that makes the rest of this page work.
Price was accurate when this page was compiled and changes often.
On this page
What are the starting AT Pro settings for each site type?
Sensitivity is quoted as a share of the machine's range rather than a fixed bar count, because the correct number is whatever your ground will carry without chatter. Turn it up until the machine becomes unstable, then come back two notches.
A Garrett AT Pro runs roughly 70 to 80 percent sensitivity in a mild park, 50 to 65 percent on wet salt sand where a single frequency machine struggles, and near maximum only in clean low mineral field soil.
| Site | Mode | Sensitivity | Iron Audio | Ground balance | Note |
|---|---|---|---|---|---|
| Mown park, high trash | Coins | 70 to 80 percent | On | Automatic on site | Consider the 5 by 8 coil before you consider more sensitivity |
| Old school yard, deep coins | Pro mode Standard | 75 to 85 percent | Off, spot check on | Automatic, re-check hourly | Depth matters more than separation here |
| Open field, low trash | Standard or Custom | 80 to 95 percent | Off | Automatic on site | The one place near maximum sensitivity is realistic |
| Dry beach sand | Coins or Custom | 70 to 85 percent | Off | Automatic | Dry sand behaves much like mild soil |
| Wet salt sand | Standard, reduced | 50 to 65 percent | Off | Manual, re-balance often | Expect falsing. This is the machine's weak ground |
| Surf and shallow salt water | Standard, reduced | 40 to 60 percent | Off | Manual, frequently | Waterproof is not the same as saltwater capable |
| Fresh water, lake or river | Standard or Coins | 70 to 85 percent | Off | Automatic | Fresh water is far kinder than salt |
| Relic site, heavy iron | Zero or Custom | 65 to 80 percent | On | Manual, careful | Run wide open on discrimination and let the tone sort it |
| Highly mineralised red clay | Standard | 55 to 70 percent | On | Manual, re-check constantly | Ground noise, not target depth, is the limiting factor |
Starting points drawn from the AT Pro owner's manual mode descriptions and common field practice. Ground conditions vary enormously between parcels, so treat every figure here as a first guess to be tuned on site.
Can you use the AT Pro in salt water?
This needs saying plainly. Garrett publishes the AT Pro as fully submersible to 10 feet, and that rating is about water ingress, not about performance. The AT Pro is a single frequency VLF machine, and salt water is itself a conductor. On wet salt sand and in the surf, the salt signal competes with target signals, forcing you to cut sensitivity, ground balance manually and repeatedly, and accept falsing and lost depth. You can hunt a salt beach with an AT Pro, and people do, but you are working around the machine rather than with it.
If salt water is your main ground, a multi-frequency or dedicated salt machine is the honest answer. Garrett's own Garrett ACE Apex offers a Multi-Salt mode, the Garrett Vortex VX9 adds simultaneous multi-frequency with a deeper submersion rating, and outside the brand the Minelab Equinox 900 and Nokta The Legend Pro Pack both ship beach modes built for exactly this. Compare the immersion ratings on the AT series waterproof ratings page before you assume ten feet means the machine is at home in the sea.
How should you set up for a trashy park?
Parks punish the wrong coil far more than they punish the wrong sensitivity. The stock 8.5 by 11 DD sees too much ground at once in dense trash, and the fix is the 5 by 8 sniper coil rather than another trip through the menus. With the smaller coil fitted, Coins mode and around three quarters sensitivity will give you clean separation between a nail and the dime beside it.
Keep the sweep slow and low, overlap each pass by about half a coil width, and let the proportional audio do the work. If you are covering measured ground rather than wandering, the search grid planner turns a site's dimensions into lanes so you cover it once properly. The coil coverage calculator will tell you how long that actually takes.
What changes on a relic site?
Relic ground is iron ground, and discrimination is the enemy. Run Zero or a Custom profile with as little discrimination as you can stand, switch Iron Audio on so the iron speaks rather than disappears, and ground balance manually because mineralisation on old sites is rarely uniform. Sensitivity in the 65 to 80 percent range is usually the practical ceiling, because the ground noise floor arrives before the machine's depth limit does.
Expect to dig iron. The point of Iron Audio is not to avoid it but to let you choose which iron is worth a hole, and the Iron Audio settings chart explains what the feature is actually doing to the audio. A pouch with a separate trash compartment such as the Garrett Camo Digger's Pouch stops the day ending with your finds mixed into a handful of nails.
How often should you re-check ground balance?
More often than most people do. Ground balance drifts with moisture, and a beach that was balanced at the waterline is not balanced forty yards up the slope. On mild inland soil, re-checking every hour is sensible. On mineralised ground or a wet beach, re-check whenever the machine starts chattering or whenever you move to visibly different ground. If you are new to the machine, work through the beginner setup and get the habit built in before you start chasing depth.
Sources
- Garrett AT Pro owner's manual, search mode and ground balance sections
- Garrett AT Pro published specification sheet, waterproof rating
- Garrett ACE Apex listing feature bullets, Multi-Salt and Multi-Flex frequency options
Frequently asked questions
What sensitivity should I run on my Garrett AT Pro?
Run it as high as the ground will carry without chatter, which in most mild inland soil is around 70 to 85 percent. Turn it up until the machine becomes unstable, then back off two notches. On wet salt sand or heavily mineralised clay the stable ceiling can drop to 50 to 65 percent. Maximum sensitivity in noisy ground finds less, not more, because the false signals mask real targets.
Should I use Pro mode or Standard mode on the AT Pro?
Pro mode adds Garrett proportional audio and tone roll, so signal strength and conductivity come through in the sound rather than only on the screen. Most experienced owners leave Pro mode on because it tells you about depth and target edges before you look down. Standard mode gives simpler, flatter tones, which some people prefer in very noisy ground or when they are learning the machine.
Is the AT Pro good on the beach?
On dry sand, yes, it behaves much like mild soil. On wet salt sand and in the surf it is working against its own design, because a single frequency VLF machine reads salt water as a conductor. You can hunt salt beaches with it by cutting sensitivity and ground balancing manually and often, but a multi-frequency or salt-specific machine will be quieter and deeper on that ground.
Do I need to ground balance the AT Pro every time?
Yes, at the start of every session and again whenever the ground changes. The automatic procedure takes seconds. Moisture is the main driver of drift, so the same field balanced after rain will want rebalancing once it dries. On mineralised ground, manual balancing gives finer control and is worth learning, because the difference between balanced and nearly balanced is several inches of usable depth.
Which AT Pro mode is best for finding old coins?
Coins mode in trashy ground and Standard in cleaner ground, both in Pro mode audio. Coins mode applies discrimination that quietens most iron, which helps in parks. Standard accepts more of the scale and gives you a better chance at deep, ragged signals in an old yard. Neither mode changes raw depth capability, only what the machine chooses to tell you about.
Researched, not professional advice. This page is compiled from published specifications, manuals and owner-review consensus, not hands-on testing. Target ID numbers, depth figures and settings vary with soil chemistry, moisture, target size, depth, orientation and firmware version, so treat every figure here as a starting point and verify it against your own machine's manual and your own ground. As an Amazon Associate we earn from qualifying purchases.