# Water test kit sera 04210 — carbonate hardness (KH) measurement, 0.015 L, hanging box

**URL:** https://aio.lv/en/product--sera-03493--12056499
**Data updated:** 2026-03-12 19:40 (EET)
**Category:** Aquarium Supplies
**Manufacturer:** sera
**Manufacturer code:** 03493
**EAN:** 4001942042109
**Warranty:** 2 Years
**Availability:** Available for order
**Price:** 11.49 €
**Prices and availability valid until:** 2026-07-22 23:59
**Price without VAT (21%):** 9.50 EUR
**Can be purchased by legal entities:** Yes (invoice)
**Buy:** https://aio.lv/en/product--sera-03493--12056499

## Delivery options

| Delivery method | Delivery time | Cost |
|---|---|---|
| Office pickup (2b. Kengaraga str., Riga, Latvia, LV-1063) | 14.07.2026 | free |
| Pickup points | 17.07.2026 | 1.89 EUR |
| Courier delivery to door | 17.07.2026 | 4.99 EUR |

## Summary description

sera 04210 is a water test kit designed to measure carbonate hardness (KH). The kit comes in a hanging box and contains reagents for testing a small volume (0.015 L). It is intended for aquarium or pond water monitoring where KH measurement is required to manage buffering capacity and water chemistry for aquatic life.

## Long description

sera 04210 is a compact water test kit for measuring carbonate hardness (KH) in aquarium and pond water. Supplied in a hanging box with reagents for testing 0.015 L samples, the kit enables spot checks of buffering capacity to help manage stable water chemistry for aquatic plants and animals. The test range covers approximately 390 °dKH, allowing users to detect whether KH is within an acceptable range for their system.
Advantages
The kit provides a simple titration-style procedure that requires only small sample volumes and minimal equipment. Packaged for convenient storage or display, it is suitable for hobbyists and pond keepers who need occasional KH measurements. Included reagents are formulated to give reproducible results when instructions are followed, supporting decisions about water treatment such as KH/pH adjustments or peat filtration.
Suitable for
 Freshwater aquariums where carbonate hardness influences pH stability and plant growth
 Ponds requiring periodic monitoring of buffering capacity
 Saltwater systems for spot-checking KH levels alongside other water parameters
Key specifications
 Parameter measured: carbonate hardness (KH)
 Sample volume per test: 0.015 L
 Packaging: hanging box for retail display and storage
 Type of method: reagent-based titration test
 Intended use: aquarium and pond water monitoring
 Approximate measurement coverage: up to ~390 °dKH
How to use
Collect a 0.015 L water sample in a clean test vial and follow the included instructions to add reagents sequentially while observing the colour change. Titrate carefully until the specified endpoint colour is reached, counting the number of drops or additions as indicated to determine the carbonate hardness value. Rinse and dry test vessels after use and store reagents in a cool, dry place away from direct sunlight.
Usage recommendations
For low KH values in freshwater, consider using a KH/pH-plus product; for ponds, a balanced bio additive can help. If KH is too high in freshwater aquaria, filtering through peat can reduce carbonate hardness. Perform tests regularly and record results to track trends and guide corrective actions.

## Specifications

| Feature | Value |
|---|---|
| Package type | Hanging box |
| Volume | 0.015 L |
| Product type | Water test kit |
| Quantity per pack | 1 pc(s) |
| Measured parameters | Carbonate hardness (KH) |
| Suitable for pond water | Yes |
| Suitable for aquarium water | Yes |
| Suitable for freshwater aquarium | Yes |
| Suitable for marine aquarium | Yes |

## FAQ

### How much does the Water test kit sera 04210 — KH measurement cost, and is it available for purchase?

The price is 11.49 € (valid at the time of publication and already includes all taxes). The item is available for order — 11 pcs. are in stock, and you can place your purchase right now with delivery across Latvia and Europe or choose pickup at the Riga collection point. We offer favorable purchase terms, including the option to split the payment into convenient monthly installments. Availability and price are updated in real time, so we recommend placing your order in advance.

### If I order this product today, when will I receive my order?

If you place your order today, delivery will be as fast and convenient as possible. You will be able to pick up your order on 14.07.2026 at the Riga pickup point or choose delivery across Latvia and Europe. We carefully inspect every purchase and pack it securely for safe transportation.

### What payment options are available?

AiO.lv offers several payment methods: Bank transfer, Bank cards on-line, Apple Pay, Google Pay. All transactions are 100% secure and encrypted.

### Can this product be purchased for a company (with VAT)?

Yes. AiO.lv works with legal entities in Latvia and across Europe. The product price already includes VAT. For certain product categories, as well as for companies from other EU countries with a valid VAT number, a 0% VAT rate may apply. We issue the invoice immediately after the order is placed, support electronic BIS invoices, and automatically generate all necessary accounting documents. You can complete the purchase for a company online — simply select the company profile and choose bank transfer as the payment method during checkout.

### What is the warranty period?

All sera products come with an official 2 Years warranty. It covers all manufacturing defects and malfunctions that may occur during use. The warranty is valid at all authorized sera service centers and through AiO.lv

### Can the product be returned after purchase?

Yes, you can return the product within 14 days of purchase if you bought it as a consumer (not a legal entity). Returns are possible without giving any reason — the main condition is that the product retains its original appearance and full set of accessories. We will make the process as simple and convenient as possible: just contact our customer support team, and we will help you arrange the return.

### Where should I contact for warranty service?

For warranty-related questions you can contact the AiO.lv (SIA VSPRO) customer support team. More information about warranty service: https://aio.lv/en/warranty

### Where can I download the instructions for Water test kit sera 04210 — KH measurement?

You can download the instructions in PDF format from the “Instructions” section on the product description page. The file contains complete information about installation, setup, and usage.

## Image

https://aio.lv/img/cache/product/12056499/67592978_large.webp