# Mars Hydro vs PAR Meter

The clearest difference is in-app purchases: Mars Hydro at none against PAR Meter's 2. PAR Meter's advantage is update cadence (fortnightly vs every 2 months). On price, ads, device support and iOS requirement there is nothing between them.

Both are free to download. PAR Meter sells 2 in-app purchases, starting at $1.99 per month. Mars Hydro asks for nothing beyond the download.

Mars Hydro ships an update every 2 months, PAR Meter fortnightly. The most recent releases landed on October 27, 2026 and October 29, 2026 respectively.

## The numbers

| Metric | Mars Hydro | PAR Meter |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[2.6 (34 ratings)](https://appshunter.io/ios/app/mars-hydro/id6479227564/reviews)** | — |
| Number of ratings | **34** | — |
| Positive reviews | 26.9% of reviews | — |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 2 months | **Fortnightly** |
| Monetization | Free | — |
| Size | 52 MB | 43 MB |
| Requires iOS | 15.0 | 15.0 |
| Devices | iPhone, iPod | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [MARS TRADING RCC, INC.](https://appshunter.io/developer/1726858942) | [Contechity AB](https://appshunter.io/developer/1649290454) |

## What reviewers say

### Mars Hydro

[App page](https://appshunter.io/ios/app/mars-hydro/id6479227564)

Control your smart grow system with this app. Manage LED lights, ventilation, and monitor environmental data like CO2, temperature, and humidity for optimal plant growth. Automate your entire grow kit to mimic natural conditions.

**Highlights:** LED light control with timers and simulation, Ventilation system management, Complete grow kit automation via iHub, Environmental data monitoring (CO2, temp, humidity, PPFD), Sunrise and sunset simulation

**In-app purchases:** none


### PAR Meter

[App page](https://appshunter.io/ios/app/par-meter-grow-light-ppfd-dli/id6809813426)

**Features:** Vision Pro support

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Full Access (Month) | $1.99 | per month |
| Full Access (Lifetime) | $20.00 | one-time |


## Frequently asked questions

### Is Mars Hydro free?

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

### Is PAR Meter free?

PAR Meter is free to download, with in-app purchases available.

### Do Mars Hydro or PAR Meter have ads?

Neither Mars Hydro nor PAR Meter shows ads.

### Which is updated more often, Mars Hydro or PAR Meter?

Mars Hydro ships an update every 2 months, and PAR Meter fortnightly. Most recently, Mars Hydro was updated on October 27, 2026 and PAR Meter on October 29, 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.*