# Hardness Conversion Master vs SolarMark

The clearest difference is in-app purchases: SolarMark at none against Hardness Conversion Master's 1. SolarMark also leads on ads (none vs shown) and iOS requirement (15.1 vs 17.6). Hardness Conversion Master's advantage is update cadence (every 3 days vs monthly). On price and device support there is nothing between them.

Both are free to download. Hardness Conversion Master sells 1 one-off in-app purchase. SolarMark asks for nothing beyond the download.

Hardness Conversion Master ships an update every 3 days, SolarMark monthly. The most recent releases landed on October 22, 2026 and October 23, 2026 respectively.

## The numbers

| Metric | Hardness Conversion Master | SolarMark |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[5.0 (1 ratings)](https://appshunter.io/ios/app/solarmark/id6776068343/reviews)** |
| Number of ratings | — | **1** |
| Positive reviews | — | 100.0% of reviews |
| In-app purchases | Yes | **No** |
| Ads | Yes | **No** |
| Update frequency | **Every 3 days** | Monthly |
| Monetization | — | Free |
| Size | 259 MB | 55 MB |
| Requires iOS | 17.6 | **15.1** |
| Devices | iPhone, iPad | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [POYU WANG](https://appshunter.io/developer/1883764660) | [SolarMark Software LLC](https://appshunter.io/developer/6776062789) |

## What reviewers say

### Hardness Conversion Master

[App page](https://appshunter.io/ios/app/hardness-conversion-master/id6760411989)

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Unlock Pro | $1.99 | one-time |


### SolarMark

[App page](https://appshunter.io/ios/app/solarmark/id6776068343)

Monitor your solar power generation and battery storage systems locally and privately. Visualize real-time energy flow, get intelligent predictions, and receive protection alerts without relying on cloud services.

**Highlights:** Direct Modbus TCP polling, Live power flow dashboard, Multi-device infrastructure management, Localized weather-based generation predictions, On-device analytics ledger, Open data export (CSV), Protection alerts (no-generation, performance, thermal)

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

**In-app purchases:** none


## Frequently asked questions

### Is Hardness Conversion Master free?

Hardness Conversion Master is free to download, with in-app purchases available.

### Is SolarMark free?

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

### Do Hardness Conversion Master or SolarMark have ads?

Hardness Conversion Master shows ads; SolarMark does not.

### Which is updated more often, Hardness Conversion Master or SolarMark?

Hardness Conversion Master ships an update every 3 days, and SolarMark monthly. Most recently, Hardness Conversion Master was updated on October 22, 2026 and SolarMark on October 23, 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.*