Use case

Using a Dive Computer in a Pool: Logging, Chlorine and Practice

Pool sessions are where most divers first wear a computer, and where many experienced divers go back to practice skills, test new gear or get comfortable with a new computer's buttons before a trip. But pools are shallow, chlorinated and full of stop-start activity, which can make a computer behave in ways that surprise people.

This guide covers whether your computer will log a pool session, what to expect in the profile, how to look after it afterwards, and the drills that make a pool session genuinely useful for learning a new computer.

Will my computer log a pool session?

A dive computer starts recording when it detects you've passed a shallow depth threshold, usually after staying below it for a short time. In a deep diving pool, you'll almost certainly trigger a log. In a shallow pool, especially if you spend much of the session kneeling on the bottom of the shallow end, you may or may not.

The exact threshold depends on the model and is listed in the manual. If the pool's depth is close to it, a computer worn on a raised wrist might hover around the line, starting and stopping the dive repeatedly. That's normal behavior, not a fault.

Your manual's section on dive start and end conditions explains exactly when your model opens and closes a log, and whether either setting can be adjusted.

What pool logs usually look like

Does a pool session affect your next open-water dive?

A pool session is still time at a pressure greater than the surface, and dive computers track it the same way they track any other dive. In shallow water the effect on your next dive is usually small, but it isn't necessarily zero, and computers vary in how they handle it.

Chlorine and your dive computer

Pool water contains chlorine or other disinfectants. Occasional pool use isn't a problem for a dive computer, but chlorinated water left to dry on the case can be harsh over time on:

The fix is the same as after salt water: rinse thoroughly in clean fresh water, press each button a few times while submerged, then dry with a soft cloth and let it air-dry out of the sun. Our guide to protecting your computer from scratches and salt covers general care.

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Best mode for pool sessions

For most divers, the right mode in a pool is the same mode they'll use in open water, set exactly the same way. That has two benefits: the computer has a consistent history, and you practice with the screens you'll actually see on your trip.

• Air or nitrox mode: use whichever matches the gas you're breathing in the pool, typically air.
• Gauge mode: avoid it unless your instructor specifically asks. Many computers restrict switching back for a period afterwards.
• Freedive mode: only for breath-hold sessions, not scuba.
• Water type: pools are fresh water. If you switch to Fresh for the session, remember to switch back before an ocean trip.

Pool drills for learning a new computer

A pool is the safest, calmest place to learn how your computer behaves before it matters. These drills are about the computer, not dive skills, and they fit easily into a session your instructor or dive center is running.

1. Read the main screen at a glance. Find depth, dive time and no-deco information quickly while hovering.
2. Cycle through every screen. Learn the order so you can find compass, temperature or tank pressure without thinking.
3. Try it with gloves. If you dive cold water, practice with the gloves you'll wear on the trip.
4. Use the backlight. Check how to turn it on and how long it stays on, especially if you night dive.
5. Acknowledge an alarm. Some computers let you trigger a test alarm or set a shallow depth alarm for practice. Learn what each sounds or feels like and how to silence it.
6. Check air integration. If you have a transmitter, confirm the signal holds when you move your arm around.
7. Set a bookmark. If your computer supports it, practice bookmarking and find it later in the log.
8. Review the log afterwards. Sync it and see how your session looks. It's a good way to learn your app before the trip.

Pool vs open water: what changes

Pool gear that makes practice easier

If you practice regularly in a pool, a few items help: a mesh bag to carry wet gear, a quick-dry towel for your computer and mask, and a simple rinse container if the facility's showers are busy.

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Pool sessions for kids and new divers

For junior divers and complete beginners, the computer in the pool is mostly about familiarity. Instructors often keep it simple: look at depth, look at time, show me your computer. That's the right approach. New divers learn far more from a calm session where they check the computer regularly than from fiddling with settings.

If a new diver will use a rental computer on their trip, try to practice with the same model in the pool if the dive center has one available. Familiarity with button layout is one of the easiest ways to reduce task loading later.