Quote:
Originally Posted by ktellerman
I am in the process of cycling a new 28 gal Nano Cube HQI. The tank is in its 3rd month. Live rock/sand. Will eventually be a reef system with corals and fishes. I just added my cleanup crew last week. Even after quarantine, the rock has developed filamentous algae. Not a major problem - yet. Should I wait for the crew to do their jobs before freaking out? How long? I've read that raising the magnesium level will inhibit growth of bad algae. The water quality tests perfectly - I use DI water for top-offs and mixing with salt for changes. Any thoughts on what to do?? |
Development of green filamentous algae is a normal succession of more complex organisms that form the base of food chains in a system driven by light energy. Many of the organisms that act to keep your system running will be part of the recycling process for carbon, nitrogen and phosphorus that are currently feeding the algae growth. Cyanobacteria have bloomed and been able to fix nitrogen in the water column (along with the end-process of bacterial nitrification) so there is nitrate available for green algae growth. Organisms that have lived, died, and decomposed have contributed the small amount of phosphorus (remember, Redfield ratios are 106:16:1 for C:N:P) needed to drive these photoautotrophic growths, and as the algae grow, they begin to fix carbon from inorganic sources (CO2 primarily) that form the carbohydrates that feed the base of your critters' food chains (amphipods, copepods, bristleworms, snails, and ultimately the fishes between feedings, etc. that all depend on this source of food).
Think of it as a terrestrial pasture: you have to have grass to feed the woodland creatures so there are woodland creatures to feed the carnivores that are the apex of a particular food chain. Without grass, there will be no carnivores. The trick is to get to the point that there is enough grass to "bloom" the grazers to a population level where they control the amount of "grass" available. In addition, there are many spp. of grasses that compete for space and nutrients, and this will control the growth of the initial grass that started the succession. In your tank, you are seeing the initial speciation of the grasses, and as the tank matures and you control both imports of nutrients and remove (export) that detrital remains of both bacterial sinking and excess algae growth. This means that nutrient excesses leading to eutrophic algal blooms will stay in check. Grazers will multiply (including those at the microscopic level), and the
populations will control excess algae growth through herbivory and you will control algal bloom by removing excess nutrients and excessive biomass.
How about some pix of what you think is a problem?
I hope this makes sense to you; the green algal bloom is an essential part of the maturity of the closed-system marine aquarium. Nutrient control and good herbivory are the tools you need to keep the system looking good.
HTH
