In the 1980's, aquarium enthusiasts witnessed a transition from a rather unsuccessful adoption of freshwater filtration for saltwater -- canister and undergravel filters -- to a 'mad scientist' high-tech approach. Suddenly, people were trying to avert high death rates and algae blooms by adding every conceivable filter to the aquarium. One's understanding was not measured by the health of the fish, but, paradoxically, by how thoroughly you can recite all your filters and their brand names. A typical setup at the time would have a UV filter, a few polishing filters, carbon bags, an enormous wet-dry filter with rotating spray bars and an undersized protein skimmer. Consequently, there was a direct correlation between the vastness of the equipment and opinions on how to maintain it. The focus had shifted from the science of nature, to the nature of science.
The process evolved in the early 1990's with a devotion to what worked. Skimmers grew larger and more efficient. The wet-dry actually became smaller and more efficient or was replaced altogether by live-rock. Other components assumed a reduced role as the 'Berlin-Method' took hold as a more 'natural' alternative. Yet, in spite of greater success in sustaining live corals and fish, this method still had its drawbacks. Inhabitants could not always keep the sand or substrate well-groomed causing gas build-ups and algae blooms. And micro and macro-algae would cause stressful PH drops at night as they stripped the water of the same oxygen they helped produce.
Again taking our cues from nature, the benefits of photosynthesis were starting to gain attention from many aquarists. It was discovered that if the process of photosynthesis were able to continue somewhere within the aquarium at all times, it would replicate the natural nocturnal influx of highly oxygenated low nutrient water from the open ocean. When the display lights over the aquarium go out, other lights should go on over a section of macroalgae which is outside of the display tank (usually behind or below the tank) residing in a "RDP filter box" in which the aquarium water is cycled through. This "box" need not be more than a 10 gallon tank with plastic screening or egg-crate within it for the algae to grow on and lights above it. Every 10-14 days the screening should be removed to scrape off the excess algae. After harvesting, the screen can be rinsed with freshwater to remove unattached algae and kill any herbivorous invertebrates that may have started to colonize within the garden.
The entire harvesting process will only take a few minutes and the benefits will be well worth it as the algae will continue to remove pollutants, replenish the oxygen, and greatly contribute to the stability of a closed system.
