# Mars Legacy vs VPD Chart

The clearest difference is review sentiment: VPD Chart at 74% against Mars Legacy's 12%. VPD Chart also leads on rating (4.5 vs 1.3). Mars Legacy's advantage is in-app purchases (none vs 2) and iOS requirement (13.0 vs 15.1). On price, ratings volume, update cadence and ads there is nothing between them.

Both are free to download. VPD Chart sells 2 in-app purchases, starting at $3.99 per month. Mars Legacy asks for nothing beyond the download.

VPD Chart holds the better App Store score, 4.5 against 1.3. Both are backed by a comparable volume of ratings — 70 and 30 respectively. Written reviews point the same way: 12% of Mars Legacy's written reviews are positive against 74% of VPD Chart's.

Mars Legacy ships an update monthly, VPD Chart every 3 weeks. The most recent releases landed on August 7, 2026 and September 22, 2026 respectively.

## The numbers

| Metric | Mars Legacy | VPD Chart |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [1.3 (70 ratings)](https://appshunter.io/ios/app/mars-legacy/id1612237275/reviews) | **[4.5 (30 ratings)](https://appshunter.io/ios/app/vpd-chart/id6470015847/reviews)** |
| Number of ratings | **70** | 30 |
| Positive reviews | 12.2% of reviews | **73.7% of reviews** |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Monthly | **Every 3 weeks** |
| Monetization | **Free** | Free with in-app purchases |
| Size | 59 MB | 49 MB |
| Requires iOS | **13.0** | 15.1 |
| Devices | iPhone, iPod | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [MARS TRADING RCC, INC.](https://appshunter.io/developer/1726858942) | [INNOVO DEV S.R.L.](https://appshunter.io/developer/1814828527) |

## What reviewers say

### Mars Legacy

[App page](https://appshunter.io/ios/app/mars-legacy/id1612237275)

Control and configure your indoor grow lights remotely. Automate growth cycles with custom timers, simulate sunrise and sunset, and manage multiple lights independently from a single device. Compatible with the Mars Hydro Smart Grow System.

**Highlights:** Remote LED light control, Adjustable light intensity, Automatic growth cycle programming, Sunrise/sunset simulation, Wireless multi-light control, Independent lighting group management

**In-app purchases:** none

**What reviewers like**

- ✅ Fan control works reliably
- ⚙️ Basic on/off functionality operational
- 🎯 Good hardware quality (lights and fans)
- 💰 Reasonable price-to-quality ratio
- 📱 App concept is innovative

**What reviewers complain about**

- 🐛 Frequent disconnections (WiFi and Bluetooth)
- ⏱️ Timer functionality completely broken
- 🌅 Sunrise/sunset mode non-functional
- 🎬 Scene/automation features unreliable
- 🔄 App randomly resets or crashes

**Reported bugs**

- App cannot detect Bluetooth despite phone detecting it
- Timer settings do not execute at scheduled times
- Scenes and automation groups fail to work
- WiFi connection drops frequently and reconnection fails
- Light brightness changes unexpectedly without user input

**Requested features**

- Multiple on/off cycles per day for automation
- Daylight saving time adjustment option
- Sunrise/sunset mode with adjustable brightness levels
- Better WiFi stability and range
- Improved app interface and user experience


### VPD Chart

[App page](https://appshunter.io/ios/app/vpd-chart/id6470015847)

This app calculates Vapor Pressure Deficit (VPD) using air temperature, relative humidity, and canopy temperature. It offers real-time charting, sensor integration, and educational tools to understand plant growth environments. Organize data by zones and visualize dew point areas.

**Highlights:** VPD calculation, Interactive VPD chart, Sensor integration, Zone organization, Dew point visualization, Grow Timeline

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| VPD Chart Plus (monthly) | $3.99 | per month |
| VPD Chart Plus (annual) | $29.99 | per year |


## Frequently asked questions

### Is Mars Legacy free?

Mars Legacy is free to download, with no in-app purchases.

### Is VPD Chart free?

VPD Chart is free to download, with in-app purchases available.

### Which has better reviews, Mars Legacy or VPD Chart?

VPD Chart is rated higher. Mars Legacy averages 1.3 out of 5 from 70 ratings, while VPD Chart averages 4.5 from 30 ratings.

### Do Mars Legacy or VPD Chart have ads?

Neither Mars Legacy nor VPD Chart shows ads.

### Which is updated more often, Mars Legacy or VPD Chart?

Mars Legacy ships an update monthly, and VPD Chart every 3 weeks. Most recently, Mars Legacy was updated on August 7, 2026 and VPD Chart on September 22, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*