# Aquarist's Notes vs ctrl4U

The clearest difference is in-app purchases: ctrl4U at none against Aquarist's Notes's 2. ctrl4U also leads on iOS requirement (14.0 vs 16.4). Aquarist's Notes's advantage is update cadence (every 6 days vs every 4 months). On price, ads and device support there is nothing between them.

Both are free to download. Aquarist's Notes sells 2 in-app purchases, starting at $1.99 per month. ctrl4U asks for nothing beyond the download.

Aquarist's Notes ships an update every 6 days, ctrl4U every 4 months. The most recent releases landed on September 11, 2026 and July 8, 2026 respectively.

## The numbers

| Metric | Aquarist's Notes | ctrl4U |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | **Every 6 days** | Every 4 months |
| Size | 16 MB | 2 MB |
| Requires iOS | 16.4 | **14.0** |
| Devices | iPhone, iPad, Mac | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Ludek Slouf](https://appshunter.io/developer/1664390856) | [Eagle Kingdom Technologies(shenzhen) Co., Ltd.](https://appshunter.io/developer/1741128165) |

## What reviewers say

### Aquarist's Notes

[App page](https://appshunter.io/ios/app/aquarists-notes/id6451252680)

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Monthly subscription | $1.99 | per month |
| Annual subscription | $9.99 | per year |


### ctrl4U

[App page](https://appshunter.io/ios/app/ctrl4u/id6496848796)

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

**In-app purchases:** none


## Frequently asked questions

### Is Aquarist's Notes free?

Aquarist's Notes is free to download, with in-app purchases available.

### Is ctrl4U free?

ctrl4U is free to download, with no in-app purchases.

### Do Aquarist's Notes or ctrl4U have ads?

Neither Aquarist's Notes nor ctrl4U shows ads.

### Which is updated more often, Aquarist's Notes or ctrl4U?

Aquarist's Notes ships an update every 6 days, and ctrl4U every 4 months. Most recently, Aquarist's Notes was updated on September 11, 2026 and ctrl4U on July 8, 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.*