Re: [APD] NO3 limits in planted tanks

["S. Hieber" <shieber at yahoo_com>]

Are you claiming that nigh NO3 and PO4 levels under all
conditions do not induce algae growth? Or are the
circumstances limited in which they do not?

sh

--- Thomas  Barr <tcbiii at earthlink_net> wrote:

> 
> Well, 
> I found out that NO3 levels over 120ppm do NOT cause nor
> induce algae in any way.
> That said, it does cause certain plant species to melt
> (but not Crypts as often erronously stated in past
> literature and repeated anecdotal comments across the
> web). 
> I found the LD 50 for NO3 and Amano shrimp.
> (LD 50-> the level at which 50% of the organism is killed
> occurs over a given exposure time, often used in
> toxicology protocols) 
> 
> 3 day exposure at 100+ppm will cause them to act sluggish
> and slowly die off. 
> Fish were unaffected but showed some signs of stress.
> Some plants showed signs of slower growth or leaf melt. 
> 
> NO3 was from purely KNO3 inorganic inputs. 
> 
> This again is interesting because at 100ppm of NO3 I did
> see some negative plant response(inhibition/toxicity) but
> no algae responses. 
> 
> It seems that negative plant responses are more of an
> issue with the upper ranges of the macro nutrients rather
> than any issue of inducing algae.
> 
> I have still yet to have found any PO4 that causes plant
> inhibition.
> 
> Still, given these extremely high nutrient levels, I
> think it's very safe to say that excess nutrients over an
> extremely wide range causes no algae blooms.
> 
> Perhaps the rest of the folks on the list can explain
> this to other folks that still suggest algae or plants
> outcompete eachother for these resources(impossible
> obviously when the levels are 5ppm PO4/100ppm NO3---all
> in bioavailable inorganic forms), or that excess
> nutrients induces algae(other than NH4/unstable CO2) that
> these issues are simply not true.This will help stop
> myths that have long been established and further the
> hobby. 
> 
> I tested high levels of Trace elements a few months ago
> and found that using SeaChem's Flourish at 100
> milliliters/per 100 liters of tank (or 10mls per liter of
> tankl!!) did not cause any shrimp toxicity nor any
> negative plant response over a 7 day time frame. The
> water was very dark during this time from all the trace
> elements. 
> 
> Again, this clearly shows that excess, or high levels of
> Fe and other trace elements such copper have no adverse
> effects or impacts on flora or fauna.
> 
> So I still do not know what PO4 or trace element level is
> toxic and causes plant inhibition.
> But..........it's extremely unlikely someone wilkl make
> their water tea colored with trace elemtns or add more
> than 10 ppm of PO4.
> 
> Therefore the usable range of all needed plant nutrients
> is enormous without any negative flora or fauna impacts.
> The issue is really one of nutrient levels that are too
> low, rather than too high. 
> 
> There are limits, but they are so high that it's only in
> the context of a purposeful extreme over dosing that this
> occurs, far beyond normal hobby error.
> 
> Regards, 
> Tom Barr
> 
> www.BarrReport.com
> 
> 
>  
> 
> 
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