Chuck Wrobel writes...

Dear Bob:

I saw your presentation at the IMAC conference in Chicago, and really enjoyed it. I agree on many of your statements about all reef aquariums being different, and that they require different levels of maintenance. Your column in FAMA has taken about a great turn in representing natural filtration methods for reef aquariums. I feel that these methods are the future of our hobby, and are responsible for our increased success with many of the species that have been so difficult to maintain in the past. However, the position that you have taken in your answer in the July, 2003 issue of FAMA, really surprised me.

Sand Mail is a column which "is dedicated to those aquarists interested in using more natural filtration techniques." I feel that your response was one that would have been given for advice 10 years ago, and is taking us back to a less productive time in our hobby.

Since then, we have made great strides in learning about ecosystems and the importance of "infauna" in our sandbeds, refugiums and within our live rock structures. Dr. Ron Shimek also spoke at the IMAC, and provided us with some valuable information on the biology of these organisms, along with the "Detritus Cycle". The most important lesson that I learned from his presentation, was the fact that organisms only utilize 10% of the food that they ingest, which makes these micro-organisms especially important in a closed system. If they are not present, this left over "food" or detritus, will remain on the rocks and within the sandbed where it decays. This does result in higher levels of nitrates and phosphates, and ultimately algae problems.

A well balanced reef aquarium, is one that does not require a large amount of maintenance, nor vacuuming of the sand. You stated, "As for adding dozens of hermit crabs, which do not export their wastes, they simply make aquarium keeping unnecessarily more expensive and do not resolve the root cause!" Again, going back to the "Detritus Cycle", crabs and like organisms are part of this cycle, and their wastes should be consumed by the copepods, amphipods, and other live sand organisms. However, these organisms will not be in any number to handle this waste if they are continually vacuumed out of the system.

I have proven on many reef systems, that mechanical filtration raises the overall nitrate and phosphate levels of the system. Instead of the particulate matter being consumed by the micro-fauna, this matter is trapped in an area of the filtration that has constant water flow. From the instant that this matter is trapped, it will begin decaying. I feel that vacuuming the substrate, periodically, will have the same effect on the overall nutrient level of the system. This is due to the lack of this micro-fauna, and the resulting deterioration of the left over wastes.

One last point on the lack of micro-fauna and its effects on the nutrient levels within a reef aquarium. All healthy reef aquariums are very difficult to remove any decaying animals from. It is these small crustaceans and worms that are responsible for doing the final cleanup in the event of loosing a fish, invertebrate, or any left over food. If they are not present, I think that these systems would experience much greater fluctuations in the water parameters than would be seen in a balanced system.

Among all of the advancements that have been made in this hobby over the past 20 years, I believe that the nutritional requirements of invertebrates and corals will prove to be one of the biggest. Eric Borneman recently completed a series of articles on the Advanced Aquarist Online Magazine, which outlined the nutritional requirements of various types of corals and invertebrates. He stated in one of these articles that nutrition in the form of phyto and zooplankton along with water movement are more important than lighting levels for the health and growth of SPS corals!

Keeping an open mind, and following all of the articles, it makes sense. There is a reason that with all of our knowledge and technology that we do not experience mass spawning of corals in our captive environments. I think that he is on to something. Other authors have explained the energy taxes in invertebrates, and that photosynthesis can not provide a coral with 100% of its daily caloric intake. They need food. If they do not have food, they will not flourish, and certainly will not breed! The food that they need are bred and reared in our sand beds, live rock and refugiums. The larger the refugium, the more live rock and macro algae, equals more food for the corals and more organisms to clean up the mess, resulting in decreased nutrient levels, and healthier corals and invertebrates.

I certainly did not send this e-mail to offend you in any way, and I hope that you didn't take it so. I am certainly not an expert, and I have followed and learned from your work for many years. Keep up the good work, and I hope that I can attend another one of your presentations in the future. Thanks.

Sincerely,

Chuck Wrobel