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E.S.V. B-Ionic Calcium Buffer System Part 2 - 1 Gallon Calcium Refill


Item #: EV1341

In Stock

2-Part System: Component #2 - CALCIUM

Maintaining proper balance of calcium and alkalinity is important to the health of all organisms living in your aquarium. The 2-part B-Ionic Calcium Buffer System is the original, unique, easy-to-use, two-component liquid supplement system that has been formulated to provide highly concentrated calcium and carbonate alkalinity, as well as all other important major, minor, and trace elements in the proper ratios to maintain a healthy marine aquatic environment.

  • Replace inorganic ions lost from protein skimming
  • Maintain ionic balance of aquarium water
  • Ensure healthy fish and corals
  • Maintain proper pH levels
  • Supply calcium and carbonate alkalinity required for calcification


  • Mix equal parts with B-Ionic Calcium Buffer System - Part 1
  • Gallon-sized bottles are concentrated and will require dilution with RO/Di water prior to use
  • Start with 1 ml per 4 gallons of aquarium capacity daily
  • Do not exceed 1 ml. per gallon in a 24 hour period
  • Maintain alkalinity between 3.0 and 3.75 meq/liter (8.4 and 10.5 dKH) by testing daily and adjusting dose accordingly
  • Never allow pH to rise above 8.45

Contains 1 gallon bottle of Component #2 - Calcium Concentrate: 54,000 ppm calcium ion. 1 ml per gallon of aquarium water will raise calcium concentration by 16ppm.

*Note* This is component #2 of a 2-part buffer system. Buy Component #1 - ALKALINITY - Here.

Reef Chemistry Calculator

Use our chemistry calculator to find out how much you need to add to your aquarium.

Manufacturer information

E.S.V. Aquarium Supplies
E.S.V. Aquarium Products is a Hicksville, New York based aquarium supply company that specializes in the production of aquarium additives and supplements. Their 2-part B-Ionic Calcium Buffer System is a staple in the marine aquarium hobby and is the company`s flagship product, earning favorable reviews and rankings from hobbyists of all levels of experience. Their additives are known for being affordable, easy to administer and chemically sound. E.S.V. recently released a spray dried phytoplankton that eliminates the need to culture live phytoplankton. Granular activated carbon, coral glue, salt mix and various other supplements round out their product offerings.

5 Stars


Reviewed on
April 07, 2020

Yes, I would recommend this.


I have been using ESVs B-Ionic Alk and Cal for years. Great product to help maintain coral health.

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Reviewed on
March 31, 2020

Yes, I would recommend this.

Been Using for years-grerat product

Pros: Economical, easy to dose, does not create any algae blooms even if heavily dosed

Cons: none that I have found

Ive been using this calcium supplement for years in my 93 gallon mixed reef tank. I have tried many different calcium additives over the years only to find that they don't work as well. As soon as I dose my tank the corals react and expand more with greater polyp extension almost immediately.

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Reviewed on
March 27, 2020

Yes, I would recommend this.

Excellent 2-part

Pros: Comes in concentrated form to save weight; can by each part separately; very pure; works!

Love the ESV system. Have been using their chemicals for almost 20 years. My latest tank is relatively young, but I am getting fantastic growth and extension in all of my corals - from Zoas to SPS. I use the entire ESV family of products (salt, 2-part, trace elements). Super simple, and works like a dream.

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Reviewed on
January 17, 2020

Yes, I would recommend this.

What else can you ask for?

Pros: Easy to use

Cons: Pricey

My go to 2 part since day one in the hobby. All you have to do is add Rodi water and let it dissolve for a few days in room temperature then you're good to go. Only draw back is it's kind of pricey but I still recommend it.

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Reviewed on
December 18, 2019

Yes, I would recommend this.

ESV calcium

Pros: It works great and is easy to add to the tank.

Cons: none

I love this product and ordering from this company. I have never had any problems with my order. My tanks look great thanks to them!

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Reviewed on
November 05, 2019

Yes, I would recommend this.

Trying this

Pros: Should cover what my corals use

Cons: No cons

I have a calcium reactor on my big tank, but didn't want to spend the money on another, so going to try dosing instead

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Reviewed on
October 01, 2019

Yes, I would recommend this.


Pros: All

Cons: None

Great product been using for year and wouldn’t try anything else.

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Reviewed on
July 01, 2019

Yes, I would recommend this.

Love this stuff

This product work wonder!!!!

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Reviewed on
March 03, 2018

Yes, I would recommend this.


I have been using this along with other ESV additives. Never a problem while using it with an auto doser.

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Reviewed on
February 14, 2018

Yes, I would recommend this.


Pros: price

Cons: none

Good product at a price which can't be beat.

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