# CTX CTX-21 Alka 6kg

**Brand:** Ctx
**Category:** Piscine & spa
**Code (GTIN/SKU):** 8420381710947
**Canonical URL:** https://openreviews.io/en/reviews/ctx/ctx-ctx-21-alka-6kg-8420381710947

## Rating: 4.7/5 ★★★★★ — 13 reviews analyzed
_Confidence: high_

## At a glance

CTX CTX-21 Alka 6kg reviews: 4.7/5 based on 13 analyzed reviews, updated September 5, 2026.

Praised: treatment effectiveness.

13 reviews analyzed, all published on other sites.
Other sites: 1 source, 13 reviews, average rating 4.7/5.
How we count reviews: https://openreviews.io/en/methodology

## AI summary

This product is an alkalinity increaser in powder form, designed to raise the total alkalinity (TA) of pool water. According to user feedback, it is particularly effective at stabilizing the water balance.

## Strengths

- **Treatment effectiveness** — The product works perfectly, raising the overall alkalinity of the pool quickly and effectively.

## Frequently asked questions

- How quickly does the product work?
- Does the product dissolve easily in water?
- How much product should be added per m³?
- Is this alkalinity increaser compatible with all types of pool liners?

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_Source: OpenReviews — https://openreviews.io/en/reviews/ctx/ctx-ctx-21-alka-6kg-8420381710947_