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sera kH-Test 15 ml, 0.5 fl.oz. Aquarium Test Kits

Original price was: $12.95.Current price is: $9.00.

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Price: $12.95 - $9.00
(as of Oct 20, 2025 01:35:23 UTC – Details)


For approx. 390°dKH. In case of too low KH values we recommend sera KH/pH-plus (in freshwater) or sera pond bio balance (in ponds), in case of too high values we recommend filtering through sera super peat (in freshwater aquariums).
Is Discontinued By Manufacturer ‏ : ‎ No
Product Dimensions ‏ : ‎ 1.57 x 3.54 x 5.51 inches; 1.73 ounces
Item model number ‏ : ‎ 4210
Date First Available ‏ : ‎ September 1, 2009
Manufacturer ‏ : ‎ Sera North America, Inc.
ASIN ‏ : ‎ B0013ZEFPW
Best Sellers Rank: #157,738 in Pet Supplies (See Top 100 in Pet Supplies) #233 in Aquarium Test Kits
Customer Reviews: 4.6 4.6 out of 5 stars 1,133 ratings var dpAcrHasRegisteredArcLinkClickAction; P.when(‘A’, ‘ready’).execute(function(A) { if (dpAcrHasRegisteredArcLinkClickAction !== true) { dpAcrHasRegisteredArcLinkClickAction = true; A.declarative( ‘acrLink-click-metrics’, ‘click’, { “allowLinkDefault”: true }, function (event) { if (window.ue) { ue.count(“acrLinkClickCount”, (ue.count(“acrLinkClickCount”) || 0) + 1); } } ); } }); P.when(‘A’, ‘cf’).execute(function(A) { A.declarative(‘acrStarsLink-click-metrics’, ‘click’, { “allowLinkDefault” : true }, function(event){ if(window.ue) { ue.count(“acrStarsLinkWithPopoverClickCount”, (ue.count(“acrStarsLinkWithPopoverClickCount”) || 0) + 1); } }); });

In the case of too low KH values we recommend Sera KH/pH-plus (in freshwater) or sera pond bio balance (in ponds)
In the case of too high values we recommend filtering through Sera super peat (in freshwater aquariums)
Makes it easy to monitor the carbonate hardness in fresh and salt water
15 Milliliter / 0.5 Ounce Test Kit

Customers say

Customers find the test kit easy to use and appreciate its ability to maintain water quality. The accuracy receives mixed feedback, with some finding it very accurate while others disagree. The instructions also get mixed reviews, with several customers noting the lack of directions.

13 reviews for sera kH-Test 15 ml, 0.5 fl.oz. Aquarium Test Kits

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  1. Athena

    Worth it!
    This titration test is easy, accurate and worth it. You can easily see the color change when it happens and have confidence in the results, unlike test strips. KH or alkalinity is very important for fresh and salt water aquariums. If it’s not in the range that promotes pH stability, then the ph will shift too fast and cause harm/death to your fish and invertebrates. If you have a hard time reading test strips for KH, try this!

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  2. F.River

    I Like it
    This test work it. I tested it with RO/DI water, so I knew the exact KH.

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  3. L.W.

    dKH reading of my pond
    It help me understand the buffer between my pond and the PH reading. With a low dKH reading PH was always in jeopardy of crashing.

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  4. M. R. S.

    It works
    I like the quality of the materials, the glass vial with stopper, and the dropper itself has a nice design.As to its accuracy, it matches my API test kits, and is no more difficult to use.

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  5. Jan

    A must for your aquarium
    This test kit is a must if you own an aquarium. It helps you maintain your water quality. It is easy to use and easy to see the results.

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  6. YG

    Better than API
    Color is way more pronounced than API. With API I always had to guess the color a little, this one is very dark and pronounced, and very accurate. I tested it with remineralized water so I knew the exact KH.

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  7. ChillNVillian

    Simplest test I have found.
    There are so many of these test kits that make you discern between varying levels of the same color. This has simple instructions and results.

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  8. Max

    Inaccurate
    Not accurate! I got hanna kh meter and this is far from being correct ! It’s outside return policy and wasted so much time &money! Get a good one first kh is really important

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  9. Lino Di Mora

    Very good test

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  10. Alex

    Der sera 04210 Karbonathärte Test hat sich als zuverlässiges Instrument für die Wasseranalyse in meinem Süß- und Meerwasseraquarium bewährt. Die präzise Messung der Karbonathärte ermöglicht eine genaue Anpassung der Wasserbedingungen, um ein optimales Umfeld für Fische und Korallen zu schaffen.Die Anwendung des Tests ist einfach und die Ergebnisse sind leicht abzulesen. Die klaren Anweisungen machen ihn sowohl für erfahrene Aquarianer als auch für Anfänger gut verständlich. Die hohe Genauigkeit des Tests gibt mir das Vertrauen, dass meine Wasserparameter im idealen Bereich liegen.Die Qualität des sera 04210 Karbonathärte Tests zeigt sich in seiner Zuverlässigkeit und Wiederholbarkeit. Die robusten Materialien und die sorgfältige Verarbeitung tragen dazu bei, dass dieser Test zu einem unverzichtbaren Werkzeug in meiner Aquarienpflege geworden ist.Für Aquarianer, die eine präzise Kontrolle über die Karbonathärte ihres Wassers wünschen, ist der sera 04210 Karbonathärte Test eine empfehlenswerte Wahl. Er bietet eine zuverlässige Methode zur Optimierung der Wasserqualität und damit zur Förderung des Wohlbefindens der Aquarienbewohner.

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  11. 他力本願寺

    蓋を開けるときは平らな場所に容器全体を押し付けながら蓋だけゆっくり回すと簡単に開きます!10mlの水槽水で測れば0.5単位で測定ができるようですね。

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  12. Berto

    Un producto de gran calidad,un test muy fiable de lo mejor del mercado.lo recomiendo.

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  13. Amazon Customer

    I like it … very good

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    sera kH-Test 15 ml, 0.5 fl.oz. Aquarium Test Kits
    sera kH-Test 15 ml, 0.5 fl.oz. Aquarium Test Kits

    Original price was: $12.95.Current price is: $9.00.

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