# HydroColor vs Trap Timer

The clearest difference is update cadence: Trap Timer at weekly against HydroColor's every 6 months. On price, ads, in-app purchases and device support there is nothing between them.

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

HydroColor ships an update every 6 months, Trap Timer weekly. The most recent releases landed on June 7, 2026 and August 14, 2026 respectively.

## The numbers

| Metric | HydroColor | Trap Timer |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[5.0 (4 ratings)](https://appshunter.io/ios/app/hydrocolor-water-quality-app/id816427169/reviews)** | — |
| Number of ratings | **4** | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 6 months | **Weekly** |
| Monetization | Free | — |
| Size | 77 MB | 17 MB |
| Requires iOS | 15.0 | 15.0 |
| Devices | iPhone, iPod | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Thomas Leeuw](https://appshunter.io/developer/816427172) | [Sub Sea Sonics](https://appshunter.io/developer/1792265332) |

## What reviewers say

### HydroColor

[App page](https://appshunter.io/ios/app/hydrocolor-water-quality-app/id816427169)

This application uses your iPhone camera to measure water quality parameters like turbidity and suspended particulate matter. It guides you through image capture with a gray card reference and provides detailed analysis and data export.

**Highlights:** Camera-based water quality measurement, Estimates turbidity (0-80 NTU), Measures suspended particulate matter (SPM), Calculates backscattering coefficient, Requires photographer's gray card, GPS, gyroscope, and compass integration, Data export to computer

**Features:** macOS Compatibility

**In-app purchases:** none


### Trap Timer

[App page](https://appshunter.io/ios/app/trap-timer/id6740922725)

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

**In-app purchases:** none


## Frequently asked questions

### Is HydroColor free?

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

### Is Trap Timer free?

Trap Timer is free to download, with no in-app purchases.

### Do HydroColor or Trap Timer have ads?

Neither HydroColor nor Trap Timer shows ads.

### Which is updated more often, HydroColor or Trap Timer?

HydroColor ships an update every 6 months, and Trap Timer weekly. Most recently, HydroColor was updated on June 7, 2026 and Trap Timer on August 14, 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.*