Reef Chemistry Calculator FV ©

System Water Volume: 

Current Calcium:   ppm
Desired Calcium:   ppm

Current Alkalinity:  
Desired Alkalinity:  

Current Magnesium:   ppm
Desired Magnesium:   ppm

Volume Calculator

Ca Reactor Setup

My Reef

A graph showing possible values for calcium and alkalinity in marine aquaria. The red zone is the recommended target, the blue dot represents values in seawater and the green and brown crosses represent the current and desired levels based on your data. Each numbered zone outside of the target area has a set of directions to get back to the target.
The advice provided below is based on Dr. Randy Holmes-Farley's article on "Solving Calcium and Alkalinity Problems."  Enter the data and click anywere on the graph above to get the recommendation. Scroll down to see the warnings and acknowledgments.

     You should be very careful about the kinds of products or chemicals put into your aquarium. Many of these products require keen knowledge of how they interact with your aquarium and saltwater.
     All of the products presented should be used with full knowledge of their capabilities and limitations as many of these products may add more than just either Calcium, Alkalinity and/or Magnesium.
     If you don't know what a product does, don't use it. Consult your manufacturer.
     Given the variability of their granular size, powdered products conversion between volume and weight are approximations; for safety, use less than the calculated amount and measure the effect before adding the rest.
     Although every effort has been made to obtain accurate results and recommendations we can not assume responsibility for any problem related to the use of this calculator.

We want to thank Dr. Randy Holmes-Farley for his helpful articles
and help with some of these calculations used in this tool.
Our thanks also to M.G. Kademani for providing
the basis for the original calculator.
We also thank the supplement manufacturers for providing information
and allowing the listing of their products and corresponding data.

I welcome your comments, questions and suggestions,
please feel free to drop me an email any time

All products and their brand name are copyright of their respective owners.
Although links to this page are allowed, this calculator is only intended to provide
information in support of marine aquarists and can not be used for commercial purposes
Neither this page nor it's source code or contained data either partially
or entirely can be used in any other site commercial or otherwise.
For more specific and detailed information in the use of a product,
consult your manufacturer

UPDATES: Most Recent; Flash Version 2.0
12/20/15 v 2.2 FV -- Updated e-mail link
10/28/12 v 2.1 FV -- Added Fritz ProAquatics Products
07/10/10 v 2.0 FV -- Added Seachem Fusion
05/31/10 v 1.9 FV -- Updated warnings to dry products
12/14/07 v 1.8 FV -- Transferred to
01/16/07 v 1.7 FV -- Added Salifert's All in One
01/16/07 v 1.6 FV -- Updated B Soda and Sodium Carb. Calculations
12/26/06 v 1.5 FV -- Added Salifert Products
07/25/06 v 1.4 FV -- Added Kent's Tech CB Calcium and Buffer Supplement System
07/05/06 v 1.3 FV -- Updated concentration of OB calcium part
06/05/06 v 1.2 FV -- Added Warner Marine Products
05/17/06 v 1.1 FV -- Added ESV Bicarbonate System
05/15/06 v 1.0 FV -- Flash version was created
03/15/06 v 0.33 ---- Added Tropic Marin Bio-Calcium
02/18/06 v 0.32 ---- Added additional UOM and updated Randy's Mg notes
09/23/05 v 0.31 ---- Added MV Calcium Chloride.
08/06/05 v 0.30 ---- Added Calcium Chloride Dihydrate.
03/23/05 v 0.29 ---- Added Magnesium Chloride Hexaydrate and Anhydrous.
03/11/05 v 0.28 ---- Added Link to Volume Calculator Page.
03/08/05 v 0.27 ---- Added Updates for Seachem's supplements.
01/27/05 v 0.26 ---- Added Randy's Recipes 1 and 2 for Ca / Alk / Mg Suppl.
01/13/05 v 0.25 ---- Added Oceans Encounter Two Part and Mg Suppl.
12/02/04 v 0.24 ---- Added Two Little Fishies C-Balance Parts A and B
11/27/04 v 0.23 ---- Added Kent's Liquid Calcium; updated warning
10/30/04 v 0.22 ---- Added Mg Calculator; ppm option to alkalinity. Revised look.
03/13/03 v 0.21 ---- Added some warnings and usage comments.
02/13/03 v 0.20 ---- Added kalkwasser pH effects and warnings.
11/26/02 v 0.17 ---- Added Aquarium Systems Reef Evolution Cal, Ev SeaBuffer.
11/22/02 v 0.16 ---- Added Bionic, CaCl2, Washing Soda, liters, dKH.
11/22/02 v 0.15 ---- Added SeaChem Reef liquid products. Revised look.