# MASD  Alerting vs Reverse Flow

The clearest difference is in-app purchases: MASD  Alerting at none against Reverse Flow's 4. MASD  Alerting also leads on iOS requirement (12.0 vs 15.0). Reverse Flow's advantage is update cadence (weekly vs every 13 months). On price, ads and device support there is nothing between them.

Both are free to download. Reverse Flow sells 4 in-app purchases, starting at $2.99 per month. MASD  Alerting asks for nothing beyond the download.

MASD  Alerting ships an update every 13 months, Reverse Flow weekly. The most recent releases landed on October 19, 2026 and October 24, 2026 respectively.

## The numbers

| Metric | MASD  Alerting | Reverse Flow |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[5.0 (5 ratings)](https://appshunter.io/ios/app/reverse-flow-fire-hydraulics/id6775030535/reviews)** |
| Number of ratings | — | **5** |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 13 months | **Weekly** |
| Monetization | — | Free |
| Size | 65 MB | 8 MB |
| Requires iOS | **12.0** | 15.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Mach Alert Inc.](https://appshunter.io/developer/1472612618) | [DEREK ANDREW MURDOCK](https://appshunter.io/developer/6775030537) |

## What reviewers say

### MASD  Alerting

[App page](https://appshunter.io/ios/app/masd-alerting/id1629039048)

**In-app purchases:** none


### Reverse Flow

[App page](https://appshunter.io/ios/app/reverse-flow-fire-hydraulics/id6775030535)

This professional fireground hydraulics platform assists firefighters and pump operators in calculating complex flow rates, pump discharge pressures, and relay pumping requirements. It supports various nozzle types and allows for custom hose coefficients and elevation adjustments for accurate operational planning and decision support.

**Highlights:** Reverse Flow calculations, Required PDP calculations, Relay Pumping calculations, Split Lay analysis, Pump Chart storage, Nozzle support, Custom hose coefficients

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

**In-app purchases (4)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Reverse Flow Monthly Support $3 | $2.99 | per month |
| Reverse Flow Monthly Support $10 | $9.99 | per month |
| Reverse Flow One-Time Support $5 | $4.99 | one-time |
| Reverse Flow Pro | $4.99 | one-time |


## Frequently asked questions

### Is MASD  Alerting free?

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

### Is Reverse Flow free?

Reverse Flow is free to download, with in-app purchases available.

### Do MASD  Alerting or Reverse Flow have ads?

Neither MASD  Alerting nor Reverse Flow shows ads.

### Which is updated more often, MASD  Alerting or Reverse Flow?

MASD  Alerting ships an update every 13 months, and Reverse Flow weekly. Most recently, MASD  Alerting was updated on October 19, 2026 and Reverse Flow on October 24, 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.*