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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★★★★★ 5
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Reviewed in the United States on May 1, 2026
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DMM
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★★★★★ 5
Good stuffies for my Goldie.
Set name: Stuffed Animal Dog Toy Set (5 Pcs)
My dog is a heavy chewer so I don’t expect things to last long with him. But with that being said, he actually doesn’t go too hard on these stuffies and loves each and every one. Will they stand up to aggressive chewing? No they are stuffies. But for this price and for the quality, they are worth it for sure. Sometimes they don’t always squeak but I’m ok with that, because the constant squeaking can drive you crazy. I have a golden who can shove 3 of these in his big mouth but truly, one fits just fine. They are good sized for big dogs, it’s just that mine prefers to have his mouth stuffed like a chipmunk. He loves these stuffies and we will be ordering more for his endless toy box that I didn’t know I needed!
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Reviewed in the United States on November 12, 2025
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J. Bergstrom
Lexington, US
★★★★★ 4
Good for puppies or dogs with little to no teeth!
Set name: Stuffed Animal Dog Toy Set (5 Pcs)
Good for the most part. Definitely not made for a heavy chewer! My dog shredded all 5 plushies within a couple days. Lol She got a hold of 2 them the first night and we woke up to a plushie crime scene. Fluff was everywhere and the squeakers were in pieces in the middle. The toys were unrecognizable, and no one could possibly have identified their intended animal shapes. Our silly girl was laying next to the massacred toys with what could only be described as a prideful grin.
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Reviewed in the United States on December 28, 2025
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Rush Woman
Lowell, US
★★★★★ 5
Great assortment to keep the dog running
Set name: Stuffed Animal Dog Toy Set (5 Pcs)
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Shaunah Breuer
Birmingham, US
★★★★★ 3
Doggo Fun
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