I have already received a few letters concerning failed attempts at reef aquariums. I am somewhat dismayed at the information being provided to hobbyists as to what equipment is required in order to be successful. A common thread seems to be that many of you are trying to set up systems on very limited budgets and are not spending your money wisely, while others spend their hard-earned cash on needless pieces of equipment or elaborate automated systems.
The problem is often complicated by using small aquariums, under 75 gallons. This is not to say that small reef aquariums won’t work — they will, but you really need to understand how a reef aquarium operates to maintain a small one successfully over the long term.
One very common problem I see is that many of you have success with some organisms, but not all. My question then is, why continue to spend your money on difficult-to-keep organisms and the technology required to sustain them? Why not just stay with what does well in your system? The freshwater plant people learned this lesson a long time ago!
So, what should you do if you want to set up a reef aquarium on a limited budget? First of all, you need to understand that there are three important parameters you should concentrate on: lighting, filtration and water chemistry.
Many of the organisms you will want to keep in a reef aquarium require light, and lots of it. You cannot skimp on this parameter. The problem is that the amount of light you will need is totally dependent on the types of organisms you want to keep. If your lighting is too weak, some will do well, but most will not. If the lighting is very strong, the same applies — some corals and clams will do very well, and others will react badly to the intensity. You will then need to have areas in the aquarium where you can place organisms that require less light.
Now I know that this sounds rather vague, but until you know what you want to keep you cannot get specific about what type and amount of lighting you will need. The intensity required also depends on the depth of the aquarium used.
Within reason, it is safe to say that if you are using fluorescent lights only, the more you can put over the aquarium, the better. Or you can use the newer very high output (VHO) lamps, and use fewer of them. Metal halide lighting is generally reserved for aquariums greater than 20 inches in depth, but can be used on smaller aquariums — again depending on the organisms being kept. Signs of inadequate lighting can include excessive vertical extension in animals, such as mushroom anemones, lack of growth or stunted growth, poor color, and darkening of the tissue followed by gradual lightening as the zooxanthellae die off. Signs of too much light include lack of extension of polyps and body tissue, and excessive lightening (often rapid) of the corals.
It is very difficult to do lighting well on a limited budget unless you have access to used, industrial or bargain-priced equipment. However, this is one area you cannot afford to skimp on. Your whole system depends on it.
Filtration is a rather simple consideration for the reef aquarium — you simply need at least some form of it. Most aquarists today are still using live rock. By itself, live rock, when healthy, will easily handle the biological filtering needs of the aquarium. When combined with a live sand substrate, you have all the biological filtration bases covered.
You do not need a trickle filter for biological filtration. Save your money. The same goes for canister filters, undergravel filters and all the various hang-on-the-back doohickeys out there.
The only piece of equipment you will need is a good-quality, well designed protein skimmer (foam fractionator). There are many fine models out there that are designed for various sized aquariumsor. If you are at all handy, you can build your own. There are skimmer designs available on the Internet, CompuServe and America Online, not to mention in various books. The best designs use a dedicated water pump to feed the skimmer, allow for a large flow rate of water through the skimmer, inject a great deal of air, can be easily and thoroughly dismantled for cleaning, and have a wide neck leading to the foam collection cup.
The last point allows you to pump a great deal of water and inject a lot of air without having to worry that small adjustments in the water and/or air flow will quickly overflow your skimmer. Either continuous or periodic usage of small amounts of activated carbon will aid in the removal of organics, and prevent yellowing of the water. I am sure there are those of you out there who question what I have stated. But, based on my own experiences and those of thousands of other successful reef aquarists across several continents, the above is really and truly all you need in the way of filtration.
Water chemistry is always a bit of a mystery for many aquarists. Few understand it well, and fewer still seem to want to be bothered with it, for whatever reasons. The simple fact is that you will need to monitor and understand the water chemistry of the aquarium if you want to be successful, and if you want to be able to trouble-shoot potential problems.
There are three parameters that are essential to know when dealing with aquariums that contain calcifying organisms like coral: calcium, pH and carbonate alkalinity. Calcifying organisms require both calcium and carbonates in order to form calcium carbonate, the framework of their bodies. Calcium levels should be between 380 and 480 milligrams per liter (mg/L) to ensure good growth. Carbonate alkalinity can be measured in either milliequivalents per liter (mEq/L) or as German degrees of hardness (dKH). Some kits, such as those manufactured and sold by LaMotte and Hach, measure in parts per million (ppm) of calcium carbonate. It does not really matter which units you use because they can all be converted from one to the other. I’ll stick with mEq/L and dKH because these are what most hobbyist kits measure. To convert mEq/L to dKH, multiply by 2.8,and to convert dKH to mEq/L, divide by 2.8.
Alkalinity levels should be between 8 and 14 dKH in order to ensure good growth rates. The pH level should be maintained between 8.0 and 8.4. Although there are test kits available to measure pH, as I mentioned in last month’s column, it is much more economical in the long run to purchase a pH meter. These can be bought for under $100. If you can maintain these three sets of values then you are a long way toward being successful.
As I mentioned last month, one of the most common problems reef aquarists experience is the presence of undesirable marine algae, such as slime and hair algae. Both of these are rooted in the same common problem: excess nutrients in an unbalanced aquarium. When an aquarium is first set up it is perfectly natural to experience a bloom of these algae, which eventually subsides. The problem comes when they do not disappear or continue to reappear. At this point the aquarist must examine all sources of nutrient input. The two main culprits are nitrate and phosphate.
In today’s reef aquariums nitrate levels are usually not of concern unless there is a significant input of nitrate either through excessive feeding, the use of efficient nitrification (biological) filters or nitrate-laden top-off water used for evaporation replacement.
Phosphate can enter the saltwater aquarium through food and via top-off water. Algae can also liberate stored reserves in rock and sand. In fact, live sand beds can store a great deal of phosphate.
One paradox is that aquarists often report very low phosphate levels yet have undesirable algae problems. The problem is that hobbyist test kits only measure inorganic forms of phosphate. This is readily used by algae and corals, and removed by skimming. However, organic forms of phosphate can then become new sources of inorganic phosphate. This explains why hobbyists often report low levels of phosphate — the inorganic phosphate the kits are designed to measure is rapidly depleted, but the organic pool is still available to replenish the supply.
The key to dealing with undesirable algae is to limit the import of nutrients and increase their export. Imports can be reduced by using pure fresh water for make-up and water changes, using only high-quality foods and avoiding overfeeding. Exports can be maximized by using an efficient protein skimmer, using some activated carbon on a regular basis, and using grazers — such as tangs, crabs and other saltwater fish.