Salty Q&A: Calcium and Alkalinity Out of Whack

Question I’m having an issue with the calcium and alkalinity levels in my reef tank. Right now, the calcium is at 380ppm, which is at the low end of the acceptable range, and the alkalinity is at 10dKH, closer to the high end of the acceptable range. I’d like to get the calcium up over … [Read More]

The Best Beginner Small-Polyp Stony Corals

Upon entering the world of small polyp stony corals (or SPS), many people ask the magic question, “Which types are best for beginners?” In my opinion the most beginner-friendly choices are found in the genera Montipora, Pocillopora, Seriatopora, and Stylophora. Most of the corals I’ll discuss here are commonly available, so there should be a … [Read More]

What to Consider when Converting a Fish-only Tank to a Reef System

“Caribbean Chris” and I are very frequently asked what it takes to convert a fish-only marine aquarium to a reef system containing corals and other sessile invertebrates. Can you just go ahead and add the invertebrates? Can you modify the existing system to suit the corals, or do you have to start the whole thing … [Read More]

Techniques for Maintaining Calcium and Alkalinity in Reef Tanks

Calcium and alkalinity are vitally important chemical parameters in reef aquariums. They are used by stony corals to build their calcium carbonate skeletons. A lack of calcium and alkalinity in the water will inhibit the growth of reef-building corals and invertebrates, which will eventually lead to health problems. What is calcium? Calcium is one of … [Read More]

The Role of Magnesium in Marine Aquarium Chemistry

One of the big differences in moving from freshwater systems to saltwater systems is a greater emphasis on water chemistry. There is a pretty steep learning curve to get a handle on all the different chemical parameters, and it can be a source of frustration for many aspiring reef hobbyists. In aquariums with an abundance … [Read More]

Calcium: A Critical Element in Reef Aquariums

The stony corals, crustaceans, mollusks, and echinoderms in our marine aquariums depend on it to build their skeletons/shells/tests. Soft corals use it to build supportive structures, called sclerites, in their tissues. Of course, without it, you’ll never get a nice patina of coralline algae on your rockwork. The “it” I’m referring to is calcium, and … [Read More]

The Calcium Reactor: A Device Well Worth its Salt

A hobby like reef keeping has its fair share of intimidating technologies. I suppose it doesn’t help to call certain technologies sterilizers, fractionators, or reactors, which further instills a sense of complexity. One such device is the calcium reactor, and while I am a big proponent of having as simple a system as possible, this … [Read More]