<a href=showthread.php?s=&postid=10851867#post10851867 target=_blank>Originally posted</a> by Cierra1985
NO3's too low?!?! Is that possible?
Very much so, why would that surprise you?
Do you think they would grow in a low or a high NO3 environment and why?
They have a few advantages over eukaryotic algae. One is the ability to live on very little N and some can fix N2 gas and make NH4 as a source of N..........both very important strategies ............if..........the NO3 is very low...........no one else can grow well, so it's a good time for it to grow..........
Reefs have many pickers, cleaners, good currents, cooler temps etc.......if your tank's temp goes up, you have few pickers/cleaners or none, low current and low NO3.......Red cyano grows pretty well.
the aeration attaches sticky bubbles to many smaller algae and away it floats.
In other words, I can induce it to grow.
That inducement shows at least one cause(there may be others).
This is in a tank with other macro algae.........
Other critters and plants leach nutrients all the time into the water........even if the levels/concentration is beyond your test kit, the BGA's are not limited nor are many of the smaller noxious microalgae.
Basically the nutrients are used before you can measure them in the water column.
Still, many are under the assumption that they can limit some algae via nutrients.
Sure, larger macro algae.
The kind most want to keep............
Then say something like Caulpera goes sexual..........folks start complaining...........well, of course it went sexual if the NO3 bottom's out........it cannot grow if it's limited and times are harsh, so it goes sexual and hopefully the spores will find better (more nutrient rich) times.
BGA's are somewhat different, they look for nutrient poor regions where there's little competition and often combined with high organics.
They do fine in nutrient rich situations once well established though.
Most/many lower nutrient noxious algae tend to like NH4 over NO3 as well.
Most of the kelps and larger seaweeds and macros like NO3 rich deep upwelling regions such as the Western coast of the Americas.
Seagrasses also. These groups are not found in nutrient poor regions.
All you do is go look.
The other question is are low/absent NO3 really good, a gfoal etc?
Is less really better?
How far do folks want to take that and still be reasonable and practical?
I see plenty of fear and loathing about this on many forums/hobbyists, in the environmental issues and policy, in public perception but if you ask someone where the cut off is for a goal, it's suddenly a lot more murky...........
Is the goal really absent NO3?
Do we or does any aquarist need that little?
If not, then how much is okay?
what about the sources of NO3?
Is KNO3 or NaNO3 the same as fish food/fish waste, NH4, NO2 derived NO3?
I do not think so.
So is it the NH4 that's toxic, bad etc, or is it the NO3?
It's clearly the fishwaste/NH4 loading if you look and review any toxicology studies out there.
As far as algal inducement, I have no idea where folks get these nutty notions about NO3 inducing algae at nominal levels, but I've had trouble(eg, no successes) repeating these claims in a controlled test.
I have however, been able to induce a number of smaller noxious species using the above described method and with PO4 dosing.
Knowing what induces algae blooms is the key to understanding and controlling them. Do not treat the symtoms, treat the cause.
These species are very effective at bioassessments and being able to deduce what may be wrong in a tank without ever using a test kit.
The EPA uses these methods as well, and also does risk assessments on things like NO3.
They weigh in on things like how much NO3 is really okay for a given management goal. Not a bad approach for us either.
Regards,
Tom Barr
