SKU: 302160087

Sera Magnesium-Test (Mg)-Reagent 3 Refill Pack-3x15ml [Volume - 45ml]

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Description

Sera Magnesium-Test (Mg)-Reagent 3 Refill Pack-3x15ml [Volume - 45ml]This product is designed to measure the concentration of magnesium in a marine aquarium and includes a spare cartridge for reagent 3. Warning! Reagent 1 contains sodium hydroxide, which can cause serious burns. Keep this reagent securely stored and out of reach of children. Always wear protective gloves when handling. If the substance comes into contact with your eyes, rinse immediately with water and seek medical attention. If you experience nausea,

This product is designed to measure the concentration of magnesium in a marine aquarium and includes a spare cartridge for reagent 3.

Warning! Reagent 1 contains sodium hydroxide, which can cause serious burns. Keep this reagent securely stored and out of reach of children. Always wear protective gloves when handling. If the substance comes into contact with your eyes, rinse immediately with water and seek medical attention. If you experience nausea, consult a doctor and bring this manual with you.

A proper magnesium concentration is essential for the health of marine invertebrates and algae. A prime example is the red calcareous algae, which require substantial amounts of magnesium to form their skeletons. Natural seawater typically has around 1300 mg/l of magnesium. To create optimal conditions in your marine aquarium, it's crucial to maintain this concentration. The Sera magnesium test allows you to quickly and easily assess the magnesium level in your aquarium. You can also effectively boost magnesium levels using Sera magnesium plus.

Additionally, magnesium levels can be raised with Sera marin COMPONENT 6 magnesium. The amount of reagent needed will depend on the calcium levels in the water you are testing.

Store in a cool, dark place!

Instructions for Use:

In a marine water aquarium, maintaining an optimal magnesium level is vital for the thriving of invertebrates and decorative algae. Red calcareous algae are a great example, as they require high magnesium levels for their skeletal structure. Natural marine water contains around 1,300 mg/l, which should also be replicated in your aquarium for ideal conditions. The Sera magnesium-Test enables you to monitor your aquarium’s magnesium levels swiftly and efficiently. If you have prior testing experience with the Sera calcium-Test, this will be even easier for you. You can easily enhance the magnesium level in your marine water aquarium by using Sera marin COMPONENT 6 magnesium.

Directions for use: Shake the reagent bottles well before use! Avoid letting the tested water come into contact with aquarium or pond water!

  1. Rinse the measurement vial several times with the water you wish to test, then empty it. Dry the outside of the vial.
  2. Rinse the syringe multiple times with the water to be tested, then use it to fill the vial with 2 ml of this water.
  3. Add 6 drops of reagent 1 and shake the vial until the liquid is evenly mixed. Any cloudiness that appears will not affect the test.
  4. Add one level measuring spoon (provided in the kit) of reagent 2 to the vial and gently swirl (do not shake) until the powder has dissolved.
  5. Gradually add reagent 3 drop by drop while counting them. After every 5 drops, release pressure on the bottle to allow air to enter. Shake the vial after each drop until the color shifts from pink to blue (not violet) and remains stable for at least 30 seconds while you gently whirl the vial occasionally. Note the number of drops used.
  6. Empty and thoroughly rinse the measurement vial with tap water, then rinse it several times with the water to be tested and empty it again. Dry the outside of the vial.
  7. Use the syringe to take up 2 ml of the water to be tested and fill the vial.
  8. Add 6 drops of reagent 4 and shake the vial until the liquid is evenly mixed. Any cloudiness that appears will not affect the test.
  9. Add one level measuring spoon (included in the kit) of reagent 5 to the vial and gently swirl (do not shake) until the powder has dissolved.
  10. Add reagent 3 drop by drop while counting the drops, releasing pressure on the bottle after every 5 drops to allow air to be drawn in. Shake the vial after each drop until the color changes from red to green and remains stable for at least 30 seconds while whirling the vial occasionally. Note – you will require significantly more drops for this measurement compared to the first measurement!
  11. To find the magnesium level, subtract the number of drops used for the first measurement from the number of drops used for the second measurement. Multiply the remaining number of drops by 60 to calculate the magnesium level in mg/l. For example, if the first measurement used 4 drops and the second used 24 drops, subtracting gives you 20 drops. Multiplying 20 drops by 60 results in a magnesium level of 1,200 mg/l.
  12. Cleaning: Thoroughly clean the vial and syringe with tap water before and after each test. Close the reagent bottles immediately after use and do not switch caps. Store at room temperature and away from light. This product is intended for testing ornamental fish aquariums and pond water only.

Store in a cool, dark place!

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SKU: 302160087

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BB
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★★★★★ 4
Surface Fabric is very durable
Size: Small, Color: Hot Pink
Surface Fabric is very durable, but the squeaker didn't last two months. I have urged the manufacturer to find a strong more durable squeaker for their product. My dogs really enoys it when the speaker works. One of his 3 work. I have just bought two more he likes them so much. He takes it to bed every night to catch it once or twice before sleeping. Also loves to catch it a few times during the day.
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Reviewed in the United States on April 11, 2026
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Taraknits
Lake Worth, US
★★★★★ 5
Best. Toy. Ever. For My Superchewer!
Size: Large, Color: Skinny Green, Size: Large, Color: Skinny Green
Best toy ever! My dog destroys toys. Usually within about 15 minutes, she has de-squeakered and defluffed them. By the second day, she has tug-of-war-ed them to shreds. From the time we got this adorable dragon out of the package, she LOVED it. She set to work. It’s been a week, and while she has dewinged him, he lost his squeaker after a few days, and he looks a bit rough, he’s still in one piece! And, we’ve had HOURS of tug-of-war with minimal rips! She’s obsessed 😍 I ordered two more today. We’ve finally found the perfect toy for my baby!
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Reviewed in the United States on January 18, 2026
S
Verified Purchase
SnowshoePete
Lowell, US
★★★★★ 5
My 90 lb. Pitbull's All-Time Fave Toy
Size: Large, Color: Coral, Size: Large, Color: Coral
I ordered a plethora of new toys for Bruce to keep him occupied while I am working remotely from home. Poor guy gets so bored while I'm stuck in front of my computer 8+ hours a day. All the other toys are animated, but this one is just a big floppy chewy squeaky toy. Bruce quickly lost interest in all the other chirping, hopping, and twirling toys and fell in love with "Diny". When I opened Diny and gave it to Bruce, he had the elated and surprised look of a 3 yr old at Christmas. And he stayed that happy for hours, and then each time he picked up Diny to play. Diny became his go-to toy over all others (and there are many!). It is well made out of durable fabric, and they did not stuff it full of kapoc (I hate kapoc in dogs toys!). And it is delightfully low-tech. Normally he tears a squeaky toy apart as soon as he can isolate the squeaky mechanism. But cleverly, the squeaky box is loose in the long belly so it moves from one end to the other as the toy is handled. That made it difficult for Bruce to locate it. The toy remained in good condition for 2 weeks of near constant attention by Bruce. But yesterday he zeroed in on the squeaky box and ripped Diny to shreds. I was sad to see Diny go so soon. But boy-howdy was Bruce happy with it. I'm gonna buy another because we liked it so much. And so did I : )
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Reviewed in the United States on May 23, 2024
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Jason W
Birmingham, US
★★★★★ 5
This is one “under the radar” gem!!
Size: Large, Color: Coral
This is one “under the radar” gem!! Very strong internal squeaker and way tougher than it looks. My big 125lb Shepard-Husky mix gave it heck, then made it his new buddy. He’ll occasionally give it the business but on the whole, it’s surprisingly tough and my big boy loves it. Nice price!!
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Reviewed in the United States on May 10, 2026
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H
San Leandro, US
★★★★★ 4
Cute but small
Size: Large, Color: Skinny Green
Cute stuffy and has not yet ripped. While my dogs plays with it, the toy is a bit small for him. For reference he is 120lbs.
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