Sera Magnesium-Test (Mg)-Reagent 3 Refill Pack-3x15ml [Volume - 45ml]
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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Patrick O'Donnell
Draper, US
★★★★★ 4
Works well, but battery life is lacking
Style: 15" (2 x 2Ah)
This is a decent trimmer and gets the job done almost as well as a gas model. It has decent power (could use a little more) and is plenty light. However, the battery life stinks. One of the two batteries has already decided not to charge. It plugs in, but the charger does not blink or charge it. The terminals are clean. Of course, this happened just outside the return/support window, meaning I now have to buy a new battery just to use the trimmer. That's about half the price of the trimmer; if the other one dies, too, I may as well buy a brand new gas trimmer for the price and have the thing last for a decade or two like my last one, instead of a couple years like this one.
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Reviewed in the United States on September 6, 2023
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Verified Purchase
James
Cuba, US
★★★★★ 5
Overall very good product.
Style: 15" (2 x 2Ah)
I bought this trimmer as I had previously bought a Greenworks 24V MAX Cordless drill that uses the same battery. The batteries to buy them alone are over 50 dollars each and as this has two its a great value in that respect. I was tired of electric trimmers with cords or noisy gas powered ones that are hard to start. This so far has worked excellent. I have not had a problem with the trimmer cord breaking and having to re-wind it back onto the spool like some other trimmers I have used. It is not noisy and it is effective and easy to use. The only thing I would disagree on is it is advertised as having an Ultra lightweight design. It is not heavy or cumbersome to use but I would not call it ultra lightweight. Overall very good product.
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Reviewed in the United States on October 17, 2025
R
Verified Purchase
Roy Coffell
Bozeman, US
★★★★★ 1
Extremely diappointing
Style: 15" (2 x 2Ah)
I purchased a Greenworks Impact Wrench for my son. I was so so impressed with it that I purchased one for myself & decided to try their 2x24V 15" Cordless String Trimmer. Unfortunately just because a company makes one excellent tool doesn't mean that all their tools are good. The first problem I had with the trimmer was that it didn't come with the batteries or charger in the ad. It was supposed to have 4.0Ah batteries but came with 2.0Ah. In addition, more often than not, the manual didn't agree with actual parts & features. The trimmer requires two 24V batteries to operate. It can't be used with one battery even though it has a "low power" setting. On full power the trimmer had adequate power for most weeds but is no where near as powerful as a gas trimmer. The batteries only lasted about 20 minutes (this trimmer does not have a brushless motor). The 2 line feed head is not designed for easy reloading. In fact, it is the worst design I've ever owned. I've decided to return it & try one of their 2x24V brushless motor trimmers which should provide more power & has 4.0Ah batteries but costs significantly more.
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Reviewed in the United States on June 25, 2022
V
Verified Purchase
Vermicious Knids
Alexandria, US
★★★★★ 3
CUSTOMER SERVICE IS TRASH - edited
Style: 15" (2 x 2Ah)
I bought this product and it arrived with one battery that doesn't charge out of the two. Without 2 batteries, it won't work at all. Attempted to contact Greenworks with the number Amazon provided. They were closed on the weekends. Called Monday and the message stated that customer support closed early. Attempted using the Chat option for help. It states the model number STE304, doesn't exist, so I couldn't proceed. Called on Tuesday. I have been on hold for over an hour and still nothing. Will update. After about an hour and a half on hold (yes, the offer the option of leaving a call back number, which I didn't use as I had to work from home to access customer service when they were open. Also, they needed me to try out stuff with the batteries and give them serial numbers, etc.) The lady I spoke to spoke English and appeared to be US based. Eventually, after doing the "did you restart it" version of troubleshooting, it was indeed determined my battery didn't work and they offered to ship me a new one at no cost. I then had to dispose of my non-working battery in the proper manner, and our yearly toxic garbage pick up coincided with this, thankfully. It took time out of my work schedule to get this resolved, but the lady I spoke to was great and I did get my battery about a week or so later, which I did appreciate. Customer service needs better access esp since you have to have the physical batteries and charger to get this resolved, which you may not be able to do while working. Maybe they can't find people to work as that seems to be an issue everywhere. The weed eater works fine. Updated from one star to three based on resolving issues and a dead battery upon arrival, rather than the actual equipment working.
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Reviewed in the United States on May 7, 2024
K
Verified Purchase
K.K.
Battle Creek, US
★★★★★ 5
Recommend
Style: 2 x 2.0Ah
Works great BUT if you make this purchase go ahead and order handle extension because if you don't it will screw your low back up big time. Like I said works great cut great but I haven't tested the run time yet.
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Reviewed in the United States on May 23, 2026

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