Final Summary, April 2007 (Conclusion - part 5 of 5)
Lagoon inside my 40 gallon tank stand (March 2007):
I changed a number of variables, although the contest didnít allow time to fully test them all. I wish that I had time to test deferent temperatures, substrates, automated dosing, different water, natural nitrate production, and so forth.
I found that keeping seagrass significantly differs from macro algae tanks. While macro algae will out compete microalgae for nutrients in the water column, seagrass benefits more from nutrients in the substrate (to be fair, a number of people suggested that nutrients in the sand bed would help).
Although I wasnít able to make the seagrass thrive, I learned a great deal from this experience. Most importantly, that nutrients are critical to the survival of seagrass. If nutrients are not present in the substrate, they must be supplemented in the water column.
While hydroponics can provide enough nutrients for the seagrass, I feel that this method proves to be more difficult as nuisance algae and cyanobacteria could result. Perhaps the presence of some macro algae would have helped eliminate the microalgae. In any case, nutrient levels in the water column need to be limited.
I also believe that sustaining healthy specimens is probably easier than nursing weak ones back to health. I feel that I let my specimens decline too much before I started supplying them with the required nutrients. If I had started dosing nutrients earlier, I might have had better results
Even with the seagrass struggling, I was impressed with the efficiency of this tank to reduce both nitrates and phosphates. Seagrass appears to be an excellent method to achieve natural nutrient export.
Incorporating seagrass into the display tank might be an interesting way to prevent old tank syndrome. Using plants to control nutrient buildup (in the substrate which eventually affects the water column) would be a natural and aesthetically pleasing way to deal with this problem.
Thanks again for everybodyís interest and input; Iíve learned quite a bit. I also hope that Iíve sparked a little interest in keeping seagrass; I know that Iím thinking about keeping a larger lagoon (with a heavier bio-load) down the road.
Edited by seabass, 09 April 2007 - 08:51 PM.