Bulk Reef Supply

BRS Bulk Pharma Magnesium Chloride

Bulk Magnesium Chloride - Ultra Pure Magnesium Additive for your Reef Tank!

Keep your reef balanced - Use with BRS Pharma Magnesium Sulfate

Maintaining proper magnesium levels helps achieve the essential balance of calcium and alkalinity in your tank by preventing excess calcium carbonate precipitation. Unlike traditional Magnesium Chloride additives when dissolved with BRS Magnesium Sulfate it will dissolve crystal clear with no undissolved salts or residue left behind.

Buy in bulk and SAVE MONEY! - Resealable Packaging

  • No residue left behind
  • Mixes fast and clear
  • Designed for easy dosing
  • Pharmaceutical grade materials

General Adjustments - Fill a 1-gallon container 1/2 full of RO/DI or distilled water and then add 7 1/4 cups of BRS Magnesium Chloride and 1/2 cups of BRS Magnesium Sulfate into the container. Secure the cap on the container and shake it for about 10 seconds to help start the dissolving process. Remove the cap and fill the container the rest of the way with RO/DI or distilled water. Give the container a few more shakes and then let it sit until all the salts have fully dissolved before use.


2-Part Dosing - 
Fill a 1-gallon container 1/2 full of RO/DI or distilled water and then add 5 1/4 cups of BRS Magnesium Chloride and 2 cups of BRS Magnesium Sulfate into the container. Secure the cap on the container and shake it for about 10 seconds to help start the dissolving process. Remove the cap and fill the container the rest of the way with RO/DI or distilled water. Give the container a few more shakes and then let it sit until all the salts have fully dissolved before use.

Dosing Instructions

Choose BRS Liquid Magnesium Mix (New Pharma Pouch) option from the drop-down menu and select calculate. The result will be how much magnesium solution you will need to add to raise your aquariums water volume to the desired level. We suggest adding small amounts at a time into a high flow area of the tank, like a power heads output or a sump baffle. It is important to keep changes limited to under 100ppm or less per day to not shock your corals.

What is 2-Part Dosing?

As corals grow they consume calcium and alkalinity but to keep the levels steady in a reef tank requires the use of magnesium too, so it is more like 3-part dosing, to be honest. Reefers will use calcium chloride and soda ash (sodium carbonate) to maintain their reef tanks chemistry daily and add a magnesium supplement every couple weeks. Magnesium supplements are usually a blend of magnesium chloride and magnesium sulfate to help keep the sulfate to chloride ratio balanced in the aquarium. When starting a 2 part dosing system it is important to use a good test kit to establish a baseline. We really like using the Red Sea Reef Foundation test kit or Hanna Colorimeters for their accuracy and repeatability which leads to a much more stable reef and overall coral health. Stability is one of the keys to keeping a saltwater tank healthy over a long span of time and most reefers will set up an automated system that doses their aquariums needed additives daily removing repetitive (and forgettable) chore. There are purpose-built dosing systems like the Kamor X4, Neptune DOS, or Bubble Magus T-11 that are super easy to program and keeps everything in a compact package, but there are other options that many reefers prefer like the BRS 1.1mL dosing pumps that can be paired with a digital timer for precise and affordable dosing control. 

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