To choose the best substrate for your reef aquarium is more than just choosing what is pleasing to the eye and covers up the PVC framing used in aquascaping. Reef sand contains carbonate which helps to keep a high alkalinity and maintain pH levels. Types of sands suitable for this are coral gravel, aragonite, and crushed oyster shell.
Some aquarists prefer no sand or substrate at all, known as a bare bottom tank. Because live rock is made from carbonate and will help with the alkalinity and pH as well, having carbonate sand is not necessary . Tanks with bare bottom are easier to clean, allow higher flow rates, and have more stable control over nitrates. Overall, this is tempting, but we prefer the look of sand, even if it is more maintenance.
Traditionally grain size and depth played a large roll in decision making when undergravel filters were the norm. This filtration is no longer used by most hobbyists, however, so being able to choose smaller grains and bed depth, if any, give you many more options.
We looked at several different types of sand, one of which is called sugar sand. It is very fine and bright, but is easily disturbed. It is a very pretty sand and is ideal for deep sand beds, but we went with another type.
The sand we chose was Tonga MiniFlakes by Tropic Eden. This type of sand is 100% aragonite. We liked the size of the grains, larger than the sugar, yet small and dense.
It is not live sand and comes in 15 pound bags. The live rock we have in our tank will populate the sand over time, to make it live. We used approximately 85 pounds between our refugium and main tank, averaging about a 3 inch depth.
We rinsed the sand in a 5 gallon bucket before putting it in the aquarium, just to help eliminate any dust and dirt. Using wet sand was also helpful when putting it in the aquarium. We already had water in our aquarium so we siphoned off some water to account for displacement, and put the sand in one cup at a time.
Doing this helped to not have a sandstorm, and kept most of the sand off the rocks. Any sand that landed on the rocks was blown off by using the powerhead later, or when we put some of the siphoned water back in. It took very little time for the sand to settle.
45 minutes later most of the sand has settled. This type of sand can sometimes be hard to find and we were lucky to find it on ebay, but really like the look of it and are happy with the purchase.