| Tank Selection |
Selection of your tank can be one of the most important and expensive decisions that you will make in this hobby.
Tank Material:
Reef tanks are constructed of either acrylic or glass. Each type of tank has advantages and disadvantages which are listed below:
Acrylic vs. glass
Pros
| Very light weight. Easier to move when empty which can be important for large tanks and the final installation will be slightly lighter. |
| Acrylic is more transparent than glass. Large glass tanks tend to have a greenish tint to the glass unless special very expensive iron free glass is used for the front pane. This is sometimes called Sapphire glass. |
| Acrylic is a better thermal barrier than glass. |
| Acrylic is less likely to shatter catastrophically if it takes a hard blow. |
| Acrylic has no glued seams that may fail over time. |
| Acrylic is easier to drill for plumbing hookups |
Cons
| #1 problem is that acrylic can be easily scratched when cleaning the inside of the tank. All acrylic tanks will get covered with small scratches over time. This are not too noticeable as long as you avoid accidentally getting a piece of sand or coralline algae between the cleaning device you are using and the acrylic which can cause large scratches. |
Costs differences between the two depend largely on the size of the tank. Small tanks are always cheaper when using glass. As the tank size increases, the cost advantage starts to swing toward the acrylic tanks. Typically this occurs if you go above a 180 gallon tank size which is the largest standard glass tank.
Tank Size
This is a major decision point when setting up a reef tank that will dictate many of your future decisions. The conventional wisdom for reef tanks is the bigger the better. Unfortunately, the bigger the tank, the more expensive it is to setup and the more expensive mistakes tend to be. One the other hand, if you go too small, you will quickly outgrow the tank and it can be a little more touchy to keep consistent water parameters due to its small water volume.
Here are my recommendations:
For someone who wants to get into the hobby in a small way either due to finances or not yet sure if this is what you want to do with your spare time, a 29gal tank is a good size. It is big enough to house a reasonable array of specimens, and is fairly easy to light because it can use 24" long fluorescent tubes or a single metal halide bulb. It is also tall enough to give some vertical feel to the reef. A tank of this size is usually made of glass and an inexpensive external overflow can be used to connect to a sump below the tanks. When starting with this size of reef, you should be prepared to upgrade if the reef bug really bites you. Tanks smaller than a 29 can be used, but they start to limit what you can do with them. A 20 gallon long for instance does not give you enough height to build a decent reef structure, but it would be OK for a lagoon type setup.
A moderate size tank that works well is in the 70 gallon range. This size of tank usually has a width of 18" which allows for good aquascaping of the reef. It is large enough to build a decent long term reef that you will not quickly outgrow unless the reef bug bites hard.. The common 55 gallon size works OK, but it is only 13" wide which does not allow for as nice of a reef structure to be built.
Moving up a notch, the 120 gallon size tank is a very nice size for a reef. It is 4’ long x 2’ x 2’. The two foot width allows for great aquascaping and the two foot height allows for a nice tall reef structure while still being manageable to get ones hands down to the bottom of the tank to do maintenance or arrange corals. Being four foot long, it is generally easier to find a spot to put it than with a longer tank. It is also at the upper end of what 2 MH lamps or 4’ fluorescent lamps will adequately light. It is also at the point in tank sizes just before you have to start giving serious consideration to floor loading. A 120 gallon tank will weigh in excess of 1000lbs.
Moving up from here, there are some guidelines to keep in mind.
| One approach is to keep a two foot height and width and extend the length out. Up to 8 feet is common. Once you go past that length, the price tends to go up rapidly. |
| If the budget allows, a wider tank is almost always better than a narrow tank. 30" width is a great size and some people go 36"-48" or wider if space and budget allow for it. |
| Taller tanks tend to look nice, but consideration has to be given to how you will service the tank. Once you can no longer reach the bottom, this suddenly becomes difficult. If you are planning on using a DSB (Deep Sand Bed), which is typically 6" or so deep, this will take up that amount of tank depth and you may want to go with a deeper tank than you normally would to compensate. Another thing to bear in mind is that the higher the tank, the thicker the glass or acrylic needs to be and hence the more expensive the tank will get. |
| Taller tanks require higher intensity lights to provide adequate lighting to the bottom of the tanks. One general rule of thumb is that 175W MH lighting may be adequate for an 18" deep tank. A 24" deep tank my require 250W MH to achieve the same light penetration and a 30" deep tank may require 400W MH lamps. |
| If you are contemplating an unusual shape, such as a hex or corner tank, keep in mind that the lighting may be more difficult. Typically MH is the only lighting option, because fluorescent bulbs will not fit over the tank. |
Another point to keep in mind when selecting a tank is to maximize the ratio of water surface area to tank volume as much as possible. This is usually a cosmetic tradeoff. The more surface area, the better the gaseous exchange between the water and air will be. Tanks will large sumps and protein skimmers are less of an issue in this regard since these items aid greatly in the air/water exchange process.
