# Blue Diag App vs ChlorCast

The clearest difference is update cadence: ChlorCast at every 8 days against Blue Diag App's every 3 months. Blue Diag App's advantage is iOS requirement (11.0 vs 26.0). 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.

Blue Diag App ships an update every 3 months, ChlorCast every 8 days. The most recent releases landed on October 25, 2026 and October 14, 2026 respectively.

## The numbers

| Metric | Blue Diag App | ChlorCast |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[5.0 (1 ratings)](https://appshunter.io/ios/app/chlorcast/id6777863208/reviews)** |
| Number of ratings | — | **1** |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 3 months | **Every 8 days** |
| Monetization | — | Free |
| Size | 63 MB | 6 MB |
| Requires iOS | **11.0** | 26.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Fluidra Global Distribution S.L.](https://appshunter.io/developer/1626820054) | [Sean OBrien](https://appshunter.io/developer/6777834311) |

## What reviewers say

### Blue Diag App

[App page](https://appshunter.io/ios/app/blue-diag-app/id1508019955)

**Features:** macOS Compatibility

**In-app purchases:** none


### ChlorCast

[App page](https://appshunter.io/ios/app/chlorcast/id6777863208)

This app simplifies pool care by logging water tests, providing chemistry guidance, and forecasting chlorine levels. It helps users understand their pool's needs and maintain balanced water with practical, actionable advice.

**Highlights:** Log quick and full chemistry tests, Get chemistry fix recommendations, Forecast chlorine loss with weather data, Track test history and water changes, Manage chemical inventory, Set maintenance reminders

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

**In-app purchases:** none


## Frequently asked questions

### Is Blue Diag App free?

Blue Diag App is free to download, with no in-app purchases.

### Is ChlorCast free?

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

### Do Blue Diag App or ChlorCast have ads?

Neither Blue Diag App nor ChlorCast shows ads.

### Which is updated more often, Blue Diag App or ChlorCast?

Blue Diag App ships an update every 3 months, and ChlorCast every 8 days. Most recently, Blue Diag App was updated on October 25, 2026 and ChlorCast on October 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.*