Continued from page 1The reef aquarium has seen a lot of recent improvements towards replicating mother nature filtration methods from when the concept was first introduced. The transition from under gravel biological filters to wet/dry filtration was an understandable evolution for the marine aquarist and one easily excepted. In the early 80's the under the cabinet wet/dry contraptions with spinner bars and/or drip plates passing water over DLS material was introduced. Then Bio-balls, block, bale, and even plastic hair curlers replaced the lava rock, porcelain beads and DLS material.
Almost anything that would grow bacteria on it and break up the water so O2 could be added and CO2 vented was used. As the reef keeping hobby continued to evolve, the US translation of the "Berlin" style of filtration enter the picture. The mentors of the reef hobby then started publishing articles telling aquarist to remove the their balls, from your wet/dry's. Perhaps this was just a male thing, but I found this required a lot of courage.
The US interpatation of the "Berlin" concept not only affected what happened under our tanks, but also affected what was happening inside the aquarium as well. Live rock was placed on egg-crate shelves so the aquarist could easily remove the detritus and help the protein skimmers maintain water quality. Later the modified US "Berlin" approach evolved and included the addition of a live sand substrate, paving the way for the Jaubert plenum technique.
Skimmers also continued to evolve with more efficient ones being introduced everyday. However, building a better mouse trap may not be the answer. While removing protein from a closed system is a very good approach, over skimming with the super efficient skimmers available today may be taking out to much of the good along with the bad.
This evolution also greatly expanded the bio-diveristy of marine-life that can be kept. Fish species, soft and hard corals and other invertebrate life forms that were once considered difficult or impossible to keep are now thriving in dedicated hobbyist aquaria.
During the years I spent in the ornamental mariculture business, I have had the opportunity to experiment with different types of systems. I have found there is more than one way to reach the same goal. The old saying "Don't fix what is not broken" applies to anyone who is happy with their present aquarium and the marine-life in side is doing fine. However, some methods seem to be easier than others to manage.
As we know the oceans' inhabitants have evolved over millions of years in the most stable environment on earth, creating an animal that has less tolerance to change than terrestrial animals. Aquatic creatures are dependent on stable water quality conditions, consistent photoperiod, water movement, habitat, and nutrition, and are adversely effected by changes in these conditions.
This art of maintaining a successful marine aquarium is slowly evolving into a repeatable science and the key ingredient in most success stories is the aquarist ability to closely replicate what Mother Nature has so carefully composed.
This evolution towards a more natural reef aquarium has also intensified the spectrum of water quality parameters we now need to be concerned about and the efficiency of our filtration methods. Water quality is a term that covers a lot of ground (or should I say water). Filtration, or the process that removes and/or converts toxins produced by the animals in the aquarium to less toxic forms is an important facet of maintaining water quality standards. Dissolved oxygen levels, lower levels of acceptable nutrients, a higher and more stable pH, alkalinity, redox, calcium and other minor trace element levels, etc., have now became important factors.
As this list of acceptable water quality criteria increased, so has the number of gadgets designed to assist in controlling each perimeter. This influx of gadgetry, and the encroaching need for a minor in marine biology (not to mention the countless hours of care needed) to maintain a reef aquarium has catapulted this hobby to a level where the average person can no longer enjoy the aesthetic beauty of a captive marine ecosystem of his/her own.
In an attempt to make aquarium keeping simpler, not more complex, the benefits of photosynthesis is now starting to gain attention among aquarists. Through the natural process of photosynthesis, pollutants within the aquarium are removed as the aquatic plants (algae) grows. The by-product of photosynthesis is life sustaining oxygen. This dual role of removing pollutants and producing oxygen makes photosynthesis a natural and efficient addition to the filtration process.
Photosynthesis occurs naturally in aquaria during the lighted photoperiod by macro and micro-algae (plants) and photosynthetic animals (clams, corals, etc.). However, what happens when the lights go out and photosynthesis stops? The once plentiful oxygen levels are no longer being replenished and, even worse, the oxygen producers now become competitors by striping the oxygen from the water and releasing carbon dioxide. The dark tank becomes a nightmare for the inhabitants. As the oxygen levels are lowered and the carbon dioxide increases, the pH is also effected changing the once ideal conditions and causing stress to the animals. This daily roller coaster ride (fluctuation) is not normal in nature.
However, if the photosynthesis process was able to continue 24 hours a day somewhere within the water column (RDP) it would duplicate the nocturnal influx of high oxygenated, low nutrient water from the open ocean. When the lights go out over the aquarium, the lights should come on over a garden of macro- algae (out of sight to the aquarist) in the RDP filter box . This "garden" of specially selected species of algae would continue to remove pollutants, replenish the oxygen, and greatly contribute to the stability of a closed system.
The RDP filter box should be designed for maximum efficiency and low maintenance. The garden of algae is grown on a plastic screen that can be easily removed for periodic harvesting. Removing the screen and scraping the mature algae off with a plastic automobile windshield ice scraper every 10 days or so will insure that the most efficient new growth is always in development.
The algae that remains attached after harvesting will rapidly regenerate new growth. After harvesting, the screen can be rinsed under freshwater to remove any unattached algae. This freshwater rinse will also kill any herbivorous invertebrates (i.e. amphipods) that may have started to colonize within the garden. The entire harvesting and rinse process takes only minutes once every ten days, but the benefits of RDP are well worth it.
Protein skimming has also been referred to as a natural method of water purification. The much sited example of foam washing up on a beach during a windy day serves as nature's way of removing proteins and other organic compounds. This purification process is replicated by aquarists within a cylinder where water and small air bubbles mix and foam is produced. Amino acids, proteins, etc. are trapped in the foam and deposited in a collection cup. While the physical removal of certain compounds from the aquarium is beneficial, too much of a good thing in this case can also have a negative effect.
Protein skimming was introduced to the aquarium hobby in the early 70's, but the over use of it has been around equally as long. Following the recommend "rule of thumb" of passing 100% of the aquarium water volume through the skimmer every 45 minutes on a continual basis is an extreme exaggeration from the example of occasional foam on the beach created by nature.
Over skimming can remove beneficial plankton (the major component in the food chain) faster than it can reproduce. It can also remove desired trace elements (especially iodine), vitamins, food, etc. which ultimately must be replenished. The replenishment process of required trace elements is either a labor intensive job which requires some degree of expertise or an expensive process that requires a number of space age gadgets.
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