# uSpectrum PAR vs Mars Hydro

The clearest difference is rating: Mars Hydro at 2.6 against uSpectrum PAR's 1.0. Mars Hydro also leads on update cadence (monthly vs every 8 months) and ratings volume (27 vs 2). uSpectrum PAR's advantage is iOS requirement (9.0 vs 15.0). On price, ads, in-app purchases and monetization model there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

Mars Hydro holds the better App Store score, 2.6 against 1.0. That said, the two scores are not equally well evidenced: Mars Hydro has 27 ratings behind it against 2, so its average is the more settled of the two.

uSpectrum PAR ships an update every 8 months, Mars Hydro monthly. The most recent releases landed on September 16, 2026 and August 11, 2026 respectively.

## The numbers

| Metric | uSpectrum PAR | Mars Hydro |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [1.0 (2 ratings)](https://appshunter.io/ios/app/uspectrum-par/id1466017397/reviews) | **[2.6 (27 ratings)](https://appshunter.io/ios/app/mars-hydro/id6479227564/reviews)** |
| Number of ratings | 2 | **27** |
| Positive reviews | — | 23.8% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 8 months | **Monthly** |
| Monetization | Free | Free |
| Size | 25 MB | 45 MB |
| Requires iOS | **9.0** | 15.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [United Power Research Technology Corporation](https://appshunter.io/developer/1501316337) | [MARS TRADING RCC, INC.](https://appshunter.io/developer/1726858942) |

## What reviewers say

### uSpectrum PAR

[App page](https://appshunter.io/ios/app/uspectrum-par/id1466017397)

This application connects wirelessly to a handheld spectral PAR meter, allowing remote analysis and configuration of light sources. It displays detailed spectral data, light source information, and absorption metrics, with options to save and share measurements.

**Highlights:** Wireless Bluetooth connection, Remote light source analysis, Save captured data, Display spectrum and CIE diagrams, View light source metrics (LUX, CCT, CRI), Share measured data via email

**Features:** macOS Compatibility

**In-app purchases:** none


### 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


## Frequently asked questions

### Is uSpectrum PAR free?

uSpectrum PAR is free to download, with no in-app purchases.

### Is Mars Hydro free?

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

### Which has better reviews, uSpectrum PAR or Mars Hydro?

Mars Hydro is rated higher. uSpectrum PAR averages 1.0 out of 5 from 2 ratings, while Mars Hydro averages 2.6 from 27 ratings.

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

Neither uSpectrum PAR nor Mars Hydro shows ads.

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

uSpectrum PAR ships an update every 8 months, and Mars Hydro monthly. Most recently, uSpectrum PAR was updated on September 16, 2026 and Mars Hydro on August 11, 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.*