# Hydronics vs ARCA OTP

The clearest difference is review sentiment: ARCA OTP at 50% against Hydronics's 33%. Hydronics's advantage is iOS requirement (11.0 vs 13.0). On price, update cadence, ads and in-app purchases there is nothing between them.

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

Hydronics ships an update every 3 weeks, ARCA OTP every 2 weeks. The most recent releases landed on June 1, 2026 and July 10, 2026 respectively.

## The numbers

| Metric | Hydronics | ARCA OTP |
| --- | --- | --- |
| Price | Free | Free |
| Positive reviews | 33.3% of reviews | **50.0% of reviews** |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 3 weeks | **Every 2 weeks** |
| Monetization | Free | Free |
| Size | 41 MB | 8 MB |
| Requires iOS | **11.0** | 13.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Pablo Cassi](https://appshunter.io/developer/1347314111) | [Administraci�n Federal de Ingresos P�blicos](https://appshunter.io/developer/888897214) |

## What reviewers say

### Hydronics

[App page](https://appshunter.io/ios/app/hydronics/id1347314112)

Control your pool's lighting and other connected devices wirelessly from your mobile device. Create custom light effects, set schedules, and even sync lights to music for an enhanced entertainment experience.

**Highlights:** Wi-Fi controlled pool lighting, Mobile app control (phone/tablet), Customizable light effects and intensity, Audio-reactive lighting, Programmable schedules for lights and other devices, Stainless steel construction, Simple installation

**Features:** macOS Compatibility

**In-app purchases:** none


### ARCA OTP

[App page](https://appshunter.io/ios/app/arca-otp/id1445710424)

Secure your access to ARCA using biometric data. This application enhances your account security with advanced authentication methods.

**Highlights:** Biometric authentication, Enhanced account security, ARCA access protection

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Hydronics free?

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

### Is ARCA OTP free?

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

### Do Hydronics or ARCA OTP have ads?

Neither Hydronics nor ARCA OTP shows ads.

### Which is updated more often, Hydronics or ARCA OTP?

Hydronics ships an update every 3 weeks, and ARCA OTP every 2 weeks. Most recently, Hydronics was updated on June 1, 2026 and ARCA OTP on July 10, 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.*