Ok, well hopefully this thread has served its purpose then and we can go on for a little bit. I am pretty well versed in this sort of thing....
Persistent ammonia (from many factors)
Where does all of this ammonia come from? It certainly should not stay ammonia for very long in a "cycled" aquarium - which means it has the ability to complete most of the nitrogen cycle.
Remove the N or P and ammonia becomes the trigger.
I am sorry, but you are confused sir - ammonia is nitrogen. In fact ammonia (
NH3), nitrite (
NO2), and nitrate (
NO3) are all nitrogenous compounds- with one being oxidized into the other by nitrifying bacteria in an aquarium AND in soil. All of which can be used by plants - so to say ammonia is the problem is not giving enough credence to nitrite which gives away to nitrate pretty quickly in a cycled aquarium (why we don't see any from our test kits....hopefully). The
exact same principle works in soil as well. If you look on a bag of fertilizer, the three numbers explain the amount of Nitrogen (N) - Phosphorus (P) - Potassium (K) which are known to be the "big three" elements all plants need in some form or another. Nitrogen is readily available since it comprises the vast majority of the atmosphere.
However, you also cannot say that plants need nitrogen and then place a firm period on the end of that statement. Plants can only use nitrogen in certain forms....guess which ones?
To defeat algae, you must understand what caused it first. Only then can it be addressed.
What causes algae then?
Sorry, Tommy Gun, but this is incorrect. I use a method known as Estimative Index to run my planted tanks, with the word estimative being the key.
Is it estimative? Yes, at first...however, if you all of a sudden have a huge explosion of algae taking over your plants, then you cut back on something, correct? You also cannot wildly guess at how much nitrogen you are adding to your aquarium - so let's say you are making an educated estimate...otherwise you are killing your fish.
You are also not adding pure nitrogen to your tank - you must be adding some form of ammonia or nitrate, one of which is highly toxic to your fish due to the laws of osmosis.
There are other mechanisms involved, and you are right to point this out. Anyhoo, I am not alone in my views. a lot of people are running these kinds of tanks and realise that nitrates and phosphates can`t be the cause of algae.
Here is the thing....and the answer to your burning question. First, not all algae are the same. It can range from phytoplankton to sea weed and everywhere in between. In fact, some things we call algae are not even algae. However, the bottom line always remains the same. Plants need multiple items to live - just like we do; we can have all of the oxygen in the world, but without food or water, we aren't going to get very far.
Scientific studies across the world all fall on one thing - algae blooms in lakes, rivers, streams are often linked to something that produces excess nutrients.
Algae cannot live without nutrients and unlike your freshwater plants, algae cannot take in nutrients from any other source other than the water....this is a huge difference that allows your plants to thrive while algae cannot; they can utilize the nutrients faster and in a more productive manner than algae can and hence, they "win" the nutrient fight.
This is also why you don't see a bunch of discussion about whether or not fluorite should be used in a SW refugium; it wouldn't help anyways. Let's focus on the marine environment for a second (although the same principles can be translated to freshwater, I know).
What is the purpose of a refugium in a saltwater tank? In short, because many of us are even more restricted as far as minimal light levels we can have to keep algae at bay but our corals alive, we are in trouble. So, then many people will suggest using RO or highly purified water. Why? Because that eliminates the possible phosphates and nitrates (including ammonia that might be a part of chloramines) that could be in tap water - luckily all necessary major and minor trace elements are already in the salt. However, that still might not work and algae blooms persist. Heck, some of us also add literally dozens of algae eaters to our SW tanks and still algae is a problem. So what many of us resort to is the use of macro algae (sea weed) of various forms...not to mention trees and shrubs in some cases (mangroves)...for one purpose; to use up excess nutrients in the water. How can this work for so many people if your theory really applies?
Let's get back to the topic at hand though. This originally started as a discussion about an algae bloom. By algae bloom, we are not talking about a bunch of hair algae, nor black beard algae, or even blue/green algae (cyano) or brown algae (diatoms) but simple, single-celled algae that is present in every aquarium I am sure. However, something created a situation in which the relative few single celled algae present were able to reproduce and thrive so much that there is enough of them to discolor the water. What I don't understand is how plants equate into that and/or how that algae bloom in an apparently unplanted tank equals your high tech tank, estimated or not. It is absolute fact that the 72 hour black out has worked for many (especially if their are no new nutrient sources being added). This is also the same principles (minus the black out part) that are used to, for lack of a better term right now, "cure" bacterial blooms.
In some ways, it is a lot like the weeds we might find in our yards....if you don't want them to live, then you pull them out of the ground - once out of the ground, they still have light, they can still be rained on, but have no ability to take in nutrients anymore; hence, they die.
Here is more about algae from a resource that is completely unrelated to an aquarium and deals with algae blooms (of all types) on a much much much larger scale:
[URL="http
/"http/www.bioremediate.com/algae.htm""]http/www.bioremediate.com/algae.htm[/URL]
Here is more information about fertilizers for non-aquatic plants:
[URL="http/"http/www.planetnatural.com/site/xdpy/kb/n-p-k-organic-fertilizers.html""]http/www.planetnatural.com/site/xdpy/kb/...ertilizers.html[/URL]
Here is a blurb about the negative effects from water shed or run-off from fertilized farmland:
[URL="http/"http/water.usgs.gov/nawqa/circ-1136.html""]http/water.usgs.gov/nawqa/circ-1136.html[/URL]
^This mentions one key term:
eutrophication - which is, according to Merriam-Webster,
the process by which a body of water becomes enriched in dissolved nutrients (as phosphates) that stimulate the growth of aquatic plant life usually resulting in the depletion of dissolved oxygen (
www.m-w.com, keyword: eutrophication)
Preventing algae is so much easier than curing it, but curing it is relatively easy if you know how. Knowing how stems from knowing what triggers it, not what feeds it in my opinion. I cannot believe that excessive nitrates or phosphates cause algae, because I have three tanks that fly in the face of this thinking.
I agree about the preventing being the best 'cure'. However, let me remind you....
The big question is how do these types of tanks run 99.9% algae free? This is a burning question that remains unanswered, which is why your asking whether planted tanks equate to unplanted tanks is an excellent one.
....that you have not given one answer to the question "what triggers algae" and in fact, seem to imply that no one knows - so what are we supposed to do?
Come Mr Gun, I am sure you know of several myths or "thou shalt nots" that are perpetuated on this forum that you could question, but choose not to.
For the record, I did not challenge you...although I admit to not being as neighborly as I should have been in my reply....I challenged the idea that UV was the best way to solve an algae bloom. And feel free to browse my posts; I challenge a lot of people on a lot of subjects.
for all of you 
