Reef Chemistry

  1. How to "Regenerate" Seachem Purigen

    Seachem Purigen is a synthetic polymer resin that removes dissolved organic matter. It also has a water-polishing quality, and it adsorbs a wide variety of chemicals. Many find this a great alternative and/or companion to Granular Activated Carbon. Purigen can be "regenerated" after it has been saturated, which is a pretty simple process - but a few tips never hurt anyone!
  2. What is Alkalinity?

    Most reefkeepers know they need to measure alkalinity, and most know it has something to do with carbonate. But what is alkalinity exactly? Why is it important? How is it measured? This article will answer those questions and give you all of the information that you need to fully understand one of the most important chemical parameters in our reef aquaria. Along with calcium, many corals also use “alkalinity” to form their skeletons, which are composed primarily of calcium carbonate. It is...
  3. DOSING RULES: Dosing 101 For Your Reef Aquarium

    The ocean is a stew of nearly every element found on earth. Each part has its uses, each part has its problems. The biggest part of reef keeping is keeping these levels in their appropriate ranges. There is however no standard rule for all corals since Soft Corals do not consume anywhere close to the amount of calcium an Acropora would per cubic centimeter. The only two rules that hold true for everything is ONLY DOSE WHAT YOU TEST FOR and NEVER DOSE MULTIPLE THINGS SIMULTANEOUSLY! How are...
  4. The Many Methods for Supplementing Calcium and Alkalinity

    There is no aspect of reef aquarium chemistry more important than calcium and alkalinity. Many of my previous articles have described various aspects of these systems in detail. In reading those articles, aquarists will note one pervasive theme: that maintaining appropriate levels of each are very important. Moreover, the easiest way to ensure that things do not go seriously wrong in adding these to the aquarium is to use additives that have balanced amounts of calcium and alkalinity. For...
  5. How Much Two Part Do I Need?

    I'm a two part doser for alkalinity and calcium (and magnesium), and have been repeatedly asked about how to figure out how much of each a new two-parter needs to dose to their tank. This article will cover: 1) Understanding Two Part Chemicals, 2) The Need for Test Kits, 3) A Video Summary on Two Part, and 4) How Much Do I Need?
  6. Refractometers And Salinity Measurement

    Salinity is one of the most important parameters measured in reef aquaria. It controls not only the salt balance between an organism and its surrounding environment, but also the levels of a host of ions in seawater that aquarists neither measure nor control independently. Consequently, aquarists must monitor salinity to ensure that organisms are not stressed by moving between aquaria of potentially different salinity, and that the salinity of the aquarium itself is controlled within ranges...
  7. Making testing easy with a magnetic stirrer

    As we all know testing our system can be time consuming and challenging. Did I time the test, right? Did I count the drops, right? Did I shake the vile long enough? After some thought, I started looking around for a way to simplify the shaking, dropping, and adding the reagent and I came up with using a lab magnetic stirrer. I use Red Sea test kits and also, I have also tried test on Salifert test kits using their vials and it works too.
  8. pH And The Reef Aquarium

    For many aquarists, pH is not something that they have much experience with aside from their aquarium. For many, pH is almost a black box measurement: something to be considered, but whose physical meaning makes little sense to them. This article will describe pH in an intuitive way (as opposed to a more rigorous, mathematical way that I have used in previous articles). While plenty of chemical mathematics can be used to determine some of the interrelationships between various water...
  9. Nitrate in the Reef Aquarium

    Introduction Nitrate is an ion that has long dogged aquarists. It is typically formed in aquaria through the digestion of foods, and in many aquaria it builds up and can be difficult to keep at natural levels. In the past, many aquarists performed water changes with nitrate reduction as one of the primary goals. Fortunately, we now have a wide array of ways to keep nitrate in check, and modern aquaria suffer far less from elevated nitrate than they have in the past. In some case, aquarists...
  10. A DIY Alkalinity Test

    Alkalinity is one of the most important measurements that a reef aquarist can make. It can become rapidly depleted in many aquaria, requiring frequent measurement in order to maintain stable levels. While hobby test kits for alkalinity can be simple to use, some aquarists find them either tedious to perform, expensive, or of questionable accuracy. This article details how one can perform DIY alkalinity tests that do not involve visualizing color changes, should be appropriately accurate,...
  11. Phosphate in the Reef Aquarium

    The phosphorus atom is one of living matter’s basic building blocks. It is present in every living creature and in the water of every reef aquarium. Unfortunately, it is often present in excess in reef aquaria and that excess has the potential to cause at least two substantial problems for reefkeepers. The first is that phosphate is often a limiting nutrient for algae growth, so when elevated it can permit excessive growth of undesirable algae (potentially including the zooxanthellae inside...
  12. Understanding Colorimetry and Your Hanna Checker® HC

    Maintaining water quality and critical parameters is the single most important aspect of having a successful aquarium. Knowing your water's parameters is usually the first troubleshooting step to any health issue arising in aquatic life and is vital to maintaining sensitive fish, coral, or other ornamentals. As aquarium technologies develop, so do the tools we use to test our water. Hobbyists are no longer constrained to simple chemical test kits, but now have a multitude of options ranging...
  13. Testing the Big 3 Parameters

    After collecting a few tests, reading threads and new tests being released all the time I decided to put this article together. Did I learn a couple of things? Yes. I have learned not to rely on just one test only, but have a couple of test on hand to check against the other. Also there is always human error in testing
  14. Optimal Parameters for a Coral Reef Aquarium: By Randy Holmes-Farley

    Optimal Parameters for a Coral Reef Aquarium One of the main roles of an aquarist with a coral reef aquarium is to ensure that the conditions are right for their tank inhabitants. There are many different attributes of the aquarium that need to be controlled, including lighting, water flow, temperature, and the concentrations of the many chemicals in the water. This article focuses on water chemistry issues, showing my recommendations for the most important of the various chemical...
  15. ZeoVit System discussion.

    Will be starting threads on the various "method's" in advance reef keeping so hobbyist can understand each method better. As with anything in this hobby there is no one way or wrong way to keep a Reef tank. Here is the FAQ from the Zeovit forum so that you can understand the basic's of the system. ZeoVit Basic Information by Shadowramy Some say that ZeoVit is just the latest ‘snake oil’ to hit the reef market, while others praise the colorful results it gets. Still others believe the...
  16. Is Marine Pure effective at reducing nitrates? We learn some valuable lessons. | BRStv Investigates

    The time has come to reveal the results of the Marine Pure test! As the thread title alludes to, we ran into some speed bumps during this test, but we still walked away with some eye opening results.
  17. Why do I have high nitrates but low phosphates?

    Here we go with another compelling episode of 52FAQ! Today, Ryan sheds some light on possible causes for imbalanced nutrients in your tank, as well as briefly touches on the Redfield Ratio. So, don your reefer thinking caps and enjoy today's episode! See you in the discussion below!
  18. My Triton Testing Results

    There are many different ions in seawater, and as reef aquarists we generally only test for a small number of these. Calcium, magnesium, “alkalinity”, nitrate, phosphate, and ammonia, for example, are relatively easy for hobbyists to test at home using kits. Other ions, however, are more difficult to evaluate because they are present at such low concentrations or are otherwise difficult to detect. Even if there was a suitable kit for every ion in seawater, buying several dozen kits would...
  19. Source Water: Choosing and Maintaining your RO/DI Filter

    Tenji is pleased to present a series of exclusive articles for Reef2Reef members. We will be delving into the various aspects of reef keeping, focusing on tried and true methods that can be implemented by aquarists of all levels. Our first installments will be concentrating on the most basic aspect that is frequently overlooked; your source water.

    Sodium Bicarbonate is an amazingly versatile powder of goodness. How many things in your life has someone said that baking soda was the answer to your problems, or at least one of the ingredients? It is obviously used for baking, but it is in quite a bit of other products you most likely use. Arm and Hammer has made its way into things like soaps, cat litters, floor cleaners, toothpaste, odor removers, and even the volcanoes from your 4th grade science projects. It has also made its way into...
  21. Calcium And Alkalinity: A Beginner’s Briefing

    Milk and batteries? What is this stuff?! You never thought keeping corals would require a slight knowledge of chemistry, did you? Do not worry! It does not have to be as scary as your high school chemistry class. In fact, I am going to make it as easy as possible to ensure people of all ages and educations can at least get started. With a quick idea of what these two words mean and how to manipulate their levels you can easily do it yourself and feel confident you are doing it right. One...
  22. Aquarium Dosing: You Have Options

    Aquarium Dosing: Brand new Reef Salt comes packed with good stuff, most of which precipitates or gets used up over time. There are many ways to replenish these things, the easiest of which is with regular water changes. Some tanks just consume far to quickly or require things that are not present in the salt used. For instances like these we use various methods of Dosing. Dosing is the act of adding chemicals to our aquarium. There are 3 methods of Dosing that we use today.
  23. Featured

    The Basics of Reef Tank Chemistry

    Reef chemistry basics brought to you by Triquatics.
  24. Featured


    If you've been looking for a checker you can use to test your Nitrates, then this article will be helpful for you. Here @Rick Mathew shares his work on developing a way to use the Hanna HI-764 for testing Nitrates.