OSTConf vs Gas Blender Toolkit
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
OSTConf
Configure your dive computer settings and parameters wirelessly. Update date, time, custom text, gas mixes, and deco settings. Compatible with recent Bluetooth-enabled dive computers.
- Read and modify settings
- Update date and time
- Set custom text
- Configure gas mixes
- Set deco parameters
- Upgrade firmware
- Retrieve device information
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OSTConf is an application for configuring your OSTC dive computer. It allows you to read and modify settings and parameters of dive computers manufactured by heinrichs weikamp GmbH. Using Bluetooth LE technology, you can retrieve device information, update date and time, custom text, set up your gas mixes and deco parameters as well as upgrading the firmware. OSTConf is compatible with recent Bluetooth-capable OSTC dive computers such as OSTC 2, OSTC plus, OSTC sport, OSTC TR, and OSTC 4. Note that due to the iOS hardware only OSTC devices with BLE are supported. OSTC4: The firmware file contains up to three parts. Please start the firmware update multiple times to ensure that all parts are updated.
Gas Blender Toolkit
This comprehensive toolkit assists scuba divers in calculating and blending various gas mixtures like trimix, nitrox, and heliox. It offers features for both partial pressure and continuous blending, cost calculation, and utilizes ideal and real gas models for accuracy. Optimized for larger screens, it serves as a successor to a previous diving application.
- Partial pressure blending
- Continuous blending
- Trimix, nitrox, heliox calculations
- Ideal and real gas models
- Cost calculation
- Top off from storage
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Gas Blender Toolkit is a comprehensive, purpose-built calculator for technical and recreational scuba divers who blend their own breathing gases. FUNCTIONS • Partial-pressure gas blending with freely configurable fill order • Continuous / delta-gas blending method • Decanting from a storage bank, with calculation of the number of possible fills • MOD / END tables for standard scuba gases • pSCR loop oxygen-reduction calculation at constant volume ratio • CCR rebreather diluent END calculator for any depth and chosen PPO2 setpoint FEATURES • Real gas (Van der Waals) or ideal gas calculations • Cost calculation for each gas fill • Fully customizable standard gas list • Accounts for gas heating during filling • Clean, fast and easy to use • Available in English, German, Russian and Spanish Gas Blender Toolkit is the completely rewritten successor to the DIR-Wetnotes app, redesigned from the ground
Screenshots
Verdict
The clearest difference is price: OSTConf at Free against Gas Blender Toolkit's $2.99. Gas Blender Toolkit's advantage is review sentiment (60% vs 25%) and update cadence (every 9 days vs every 5 months). On ads, in-app purchases, device support and iOS requirement there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
OSTConf is free to download; Gas Blender Toolkit costs $2.99 up front. Neither carries in-app purchases, so what you see is what you pay.
OSTConf ships an update every 5 months, Gas Blender Toolkit every 9 days. The most recent releases landed on November 2, 2026 and November 11, 2026 respectively.
| Parameter | OSTConf | Gas Blender Toolkit |
|---|---|---|
| Price | Free — better | $2.99 |
| Rating | — | 3.0 (2 ratings) — better |
| Positive reviews | 25.0% of reviews | 60.0% of reviews — better |
| Number of ratings | — | 2 — better |
| Update frequency | Every 5 months | Every 9 days — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free — better | Paid |
| Best chart rank | — | #98 — better |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 16.0 | 15.0 — better |
| Further details — not scored | ||
| Size | 3 MB | 3 MB |
| Age rating | 4+ | 4+ |
| Developer | Kai-Uwe Sattler | Oleg Gurevich |
Customer experience
OSTConf
Gas Blender Toolkit
In-app purchases
OSTConf
No in-app purchases
Gas Blender Toolkit
No in-app purchases
Questions
Is OSTConf free?
Is Gas Blender Toolkit free?
Do OSTConf or Gas Blender Toolkit have ads?
Which is updated more often, OSTConf or Gas Blender Toolkit?
Other comparisons
