Aeropars said:
Surely nutrients have to come into it because algae is also a plant lifeform, albeit an unwated one. I freshly cycled tank filled with tap water is more prone to algae blooms than a cycled tank filled with mainly RO water surely? I know that in my experience this was the case.
Hi,
No, not really. This is a common misconception which is primarily why there are so many tanks suffering algal blooms. Study this thread carefully:
viewtopic.php?f=19&t=905
It's rather long winded but well worth the patience. You would be surprised to learn that in nature, freshwater algal blooms only appear in nutrient poor waters. It's important to be clear about the difference between
inducing algae versus
growing algae. The default mode of algae is in the form of spores, which, through various sensor mechanisms, monitor the condition of the environment. When the environment is favorable, the spores trigger a change and the bloom occurs. For algae, a favorable environment is one in which there is decay and pollution. Ironically, algae function as scavengers to actually clean up the environment by removing the products of decay characterized by high organic waste content and ammonia.
Once algae has been induced, then, yes they are opportunists and will feed voraciously on whatever nutrients are available in the environment. In a poorly managed tank algae is induced by the ammonia produced by organic waste and then proliferates because of the nutrients present. This becomes an optical illusion as many assume that the nutrient levels
caused the algae.
One of the main reasons a tank is at it's most vulnerable to algae attacks during setup is specifically due to the imbalance between ammonia and the population of other organisms which can feed on ammonia and thereby reduce it's concentration. This is the mechanism of the nitrogen cycle. When a tank is cycled the first product produce unsurprisingly is ammonia which is driven to high concentration levels until a specific population of bacteria can develop which feed on the ammonia and oxidize it to nitrite (NO2). The rise in ammonia in the presence of light triggers alga blooms. I can guarantee you 100% that this procedure occurs in exactly the same way whether the water is 100% RO or tap. RO water does nothing to stem the tide of ammonia buildup. If you experienced less blooms when using RO then there was some other factor or factors which led to less blooms. It cannot be attributed to RO water alone. There are so many variables in the ecology of a tank that it is easy to draw correlations between unassociated factors. You would have to review your entire management scheme and your procedures to compare between various tank setups.
It is specifically for this reason that in the first 6 to 8 weeks of a tank setup multiple and large water changes per week are critical to success. The water changes lowers the ammonia concentration thereby suppressing the algal trigger mechanism. After a few months the billions of bacteria required to stabilize the ammonia production in the tank develop and thus less frequent changes are required.
A low light tank lacks the dynamics of a high light tank specifically because of the low light. The metabolism of the plants is greatly reduced, the organic waste content is reduced and the plants ability to recycle organic waste is given enough time because the low light suppresses the algal trigger mechanism, even in the presence of ammonia. Therefore to answer your question, yes dosing EI on a low light tank results in less likelihood of algae. Of course, you would dose less since the plants would not need as much nutrients under low light conditions.
Hope this helps.
Cheers,
It is a big misconception that nutrients cause algae - people spent a lot of effort trying to dose just enough, measuring constantly, but EI throws that out the window and gets just as good results, if not better because there is more margin of error. You need to focus on avoiding the triggers that cause algae, namely:
