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Dalton 1.3.1: Dive Profile Gas Volume Correction

Dalton 1.3.1 corrects Dive Profile Advisor gas volumes on iPhone, iPad, and Mac when SAC is entered in cu ft/min, refuses Best Mix requests that no mix can satisfy, and updates Dalton for iOS 27 and macOS 27.

Dalton 1.3.1 is available now on iOS, iPadOS, macOS, and Android. It corrects a gas volume error in the Dive Profile Advisor on iPhone, iPad, and Mac, tightens several gas calculations on every platform, and updates Dalton for iOS 27 and macOS 27. If you plan with a SAC rate in cu ft/min on an Apple device, read the first section before your next dive.

Dive Profile Advisor: volumes with a cu ft/min SAC rate

On iPhone, iPad, and Mac, earlier versions of the Dive Profile Advisor calculated gas volumes in the unit of your SAC rate, then labelled the result “L”. With a SAC rate in cu ft/min, the segment, transit, total, and stress-factor volumes were shown in cubic feet under a litre label – about 28 times lower than the true volume in litres.

For example, a SAC rate of 0.7 cu ft/min at 100 ft for 20 minutes showed a total of 60 L. The correct total is about 1,689 L.

Dalton 1.3.1 converts the SAC rate before calculating, so these volumes now show true litres.

Who is affected. Divers whose SAC unit was cu ft/min. That is Dalton’s default unless the Measurement System on your iPhone, iPad, or Mac is set to Metric. SAC rates entered in L/min were not affected. Dalton for Android already calculated these volumes correctly.

What to do. Re-check any Dive Profile Advisor plan whose gas volumes came from an earlier version, including result cards you shared. Anyone who received one of those cards should re-check it as well.

Other corrections

These apply on iOS, iPadOS, macOS, and Android.

  • Best Mix no longer falls back to Air when no nitrox mix stays within your ppO2 limit at the requested depth. It shows no result and says that no nitrox mix meets the selected depth and oxygen limit. Best Mix checks oxygen only; assess narcosis and gas density separately.
  • Minimum Operating Depth now uses a more conservative planning minimum ppO2 of 0.18, up from 0.16, and rounds up at the displayed precision. MOD rounds down. Both depth limits now round in the conservative direction.
  • END is calculated to the same 200 m (about 656 ft) limit on every platform, in either depth unit. Previously, Dalton for iPhone, iPad, and Mac could not calculate END deeper than 200 ft (about 61 m) when working in feet, and left the value out. When END cannot be calculated, Dalton now shows that it is unavailable.
  • Shared calculations keep every input for all seven tools across Android, iOS, and macOS. Automatic gas selection in the Dive Profile Advisor now produces the same gases, warnings, and switch depths on every platform. Invalid links are rejected before they change the current calculation, and helium and hypoxic gases still require Technical Diver mode.

Platform updates

  • Dalton is updated for iOS 27 and macOS 27.
  • On Android, every supported language is now included in the app, so switching Dalton’s language works offline.

Verify independently

Dalton is a verification tool. It is not a decompression planner and does not replace your training or your judgment. Verify calculations independently before diving.

Dalton 1.3.1 is available on the App Store, the Mac App Store, and Google Play.