VERY interesting article about cyano/algae breakout in low nutrient tanks
- Thread starter reefrad
- Start date
HighlandReefer
Team RC
Nice article. 
One thing to keep in mind regarding trying to reduce phosphate to control algae/cyano, is that phosphate is being added every time you feed your fish in large quantities. Using lower phosphate food will help. Removing the organic debris and algae/cyano on a daily basis will help export the phosphate & nitrate as discussed in the article. There is some research that indicates many species of algae & certainly cyano are capable of deriving their phosphate needs directly from the food sources and other organic phosphate in the water column in addition to inorganic phosphate. For this reason I don't believe this article emphasized the reduction of the dissolved organic material in the water column enough. Regular water changes, good skimming, running GAC, using filter bags and running additional filtration like diatom filters will certainly aid in reducing this organic matter.
One thing to keep in mind regarding trying to reduce phosphate to control algae/cyano, is that phosphate is being added every time you feed your fish in large quantities. Using lower phosphate food will help. Removing the organic debris and algae/cyano on a daily basis will help export the phosphate & nitrate as discussed in the article. There is some research that indicates many species of algae & certainly cyano are capable of deriving their phosphate needs directly from the food sources and other organic phosphate in the water column in addition to inorganic phosphate. For this reason I don't believe this article emphasized the reduction of the dissolved organic material in the water column enough. Regular water changes, good skimming, running GAC, using filter bags and running additional filtration like diatom filters will certainly aid in reducing this organic matter.
I agree with you. However I believe the author's main point was that even though the water column could be clear of dissolved phosphates there could exist low PH regions, i.e. in the substrate, where precipitated phosphates dissolve and are subsequently available for uptake by microalgae.
In my case I have 0.00 phosphates measured with a hannah meter multiple times, no nitrates measured with an API test kit and pale SPS. i clean teh glass once a week. All of this points to a low nutrient water column. However I also have a patch of cyano on the substrate that doesnt seem to mind. I have used kalkwasser for a year so it is conceiveable that I precipitated quite a bit of phosphates way back when I didnt have low nutrients in the water column.
In my case I have 0.00 phosphates measured with a hannah meter multiple times, no nitrates measured with an API test kit and pale SPS. i clean teh glass once a week. All of this points to a low nutrient water column. However I also have a patch of cyano on the substrate that doesnt seem to mind. I have used kalkwasser for a year so it is conceiveable that I precipitated quite a bit of phosphates way back when I didnt have low nutrients in the water column.
HighlandReefer
Team RC
FWIW, phosphate attached to rock or calcium carbonate deposits will leach back into the water system dependent on the concentration of phosphate in the water column. If the phosphate level is extremely low (due to proper use of GFO), I would think this source of phosphate would be insignificant compared to what is added through fish foods. I would think reducing DOC in the water column would be much harder than reducing phosphate using GFO.
FWIW, I do not agree that all that was written there has been demonstrated, but some aspects of it may certainly happen.
One does not need to implicate limewater to have phosphate bind to live rock and sand. It will do that all on its own and can then come back off just as described, either as the pH changes or the phosphate concentration changes.
It has been postulated and even proven that the long-term use of Kalkwasser precipitates phosphates out of the water
One test by Craig Bingman. Never seen another. Probably true.
and that these phosphate based compounds settle on and in the live rock in the aquarium
I'm fairly confident that has never been shown.
Where would this occur and why? Can this, in fact, occur at all? The answer is yes in all cases demonstrated by empirical evidence that such micro algae outbreaks do occur (the reports by the hobbyists).
So, we are proving that it can happen, because algae grows? :lol:
There may be some nugget of truth in these statements, and it has been speculated about for many years. The zeovit people seem to avoid limewater for this reason.
But there is another, much more common and much clearer reason why algae grows when nutrients are low: the simple fact that lots of growing algae is able to suck up a lot of nutrients very quickly. Just like a lot of macroalgae in a refugium, a lot of growing microalgae will reduce nutrients quite well, but still be a mess of a problem.
One does not need to implicate limewater to have phosphate bind to live rock and sand. It will do that all on its own and can then come back off just as described, either as the pH changes or the phosphate concentration changes.
It has been postulated and even proven that the long-term use of Kalkwasser precipitates phosphates out of the water
One test by Craig Bingman. Never seen another. Probably true.
and that these phosphate based compounds settle on and in the live rock in the aquarium
I'm fairly confident that has never been shown.
Where would this occur and why? Can this, in fact, occur at all? The answer is yes in all cases demonstrated by empirical evidence that such micro algae outbreaks do occur (the reports by the hobbyists).
So, we are proving that it can happen, because algae grows? :lol:
There may be some nugget of truth in these statements, and it has been speculated about for many years. The zeovit people seem to avoid limewater for this reason.
But there is another, much more common and much clearer reason why algae grows when nutrients are low: the simple fact that lots of growing algae is able to suck up a lot of nutrients very quickly. Just like a lot of macroalgae in a refugium, a lot of growing microalgae will reduce nutrients quite well, but still be a mess of a problem.
While I would agree with you Randy that in the case of an aquarium filled with GHA it would come as no surprise that the phosphates are low (being used up), I believe there is an easy way to test this. I recently turned off my lights for 3 days. The cyano receded completely. This would mean that the phosphate should be released back into the water column and should be detectable with a hannah meter. In my case the phosphates did not rise even after 3 days of dark. I am assuming that without light photosynthetic dependent growth is stopped and phosphate is no longer taken up.
So my conclusion is that I have no dissolved phosphates in the column and that the cyano is feeding off something in substrate.
So my conclusion is that I have no dissolved phosphates in the column and that the cyano is feeding off something in substrate.
Re: This would mean that the phosphate should be [was] released back into the water column and should be detectable with a hannah meter.
The above statment is not necessarily true ( in my oppinion). The P could exist in forms that are not measurable by the test method, and/or as it is a limiting nutrient for the entire system, other bacteria and plants could have captured it and used it almost instantly as pretty much every living thing in the system is competing to meet its needs.
The above statment is not necessarily true ( in my oppinion). The P could exist in forms that are not measurable by the test method, and/or as it is a limiting nutrient for the entire system, other bacteria and plants could have captured it and used it almost instantly as pretty much every living thing in the system is competing to meet its needs.
HighlandReefer
Team RC
In addition cyano bacterial will take other forms when the lights are out, and survive. They may not release any or very little phosphate or nitrate when doing this. Once the lights come back on they will then resume the forms we are familar with.
If you don't mind spending a fair chunk of money, Hach makes a total phosphorus kit that measures forms of phosphate and phosphorus-containing chemicals that the Hanna meter can't detect. Also, the Hanna meter is only stated to be accurate to +- 0.04 ppm of phosphate, so I'm not sure that your experiment demonstrates that the water column gained no phosphate. It's also possible that the phosphate was removed or bound via a skimmer or some other mechanism when the cyanobacteria died back.
mr.maroonsalty
New member
Blue-green algae are suppose to be one of the earliest organism, and a few theories credit it for saving life on the planet at least once; I'm not yet loosing sleep over having a wee bit of cyano, because if anything it keeps me on my nutrient control toes, driving me to keep improving my husbandry tools and techniques.
