Hi..

Ghost shrimp and Daphnia make excellent
toxicity test critters.

Well across the years my water flies in barrels and summer
ponds have demonstrated how resistant they can be. They
have been survived "significant" (lol) changes in water
quality. Don't know about ghost shrimps but I'm familiar
with chinese freshwater shrimps that are very restistant,
too..

These can be tested in small tanks (Jars) with water
sprite and light etc to see the effects on KNO3 dosing on
them.

Yeah, I know about tiny tanks - I'm a Nano Marco.. :-)

You'll note, the article suggest rather high levels for a
number of species of invertebrates, however, the group as
a whole is much more sensitive to NO3 than are most fish
on the list.

Is the referenced article available online..?

While not specific to each species, the article gives
fairly significant support to the claims many have placed
on low NO3 causing issues, rather, I would suggest, it is
NH4, and NO3 is namely a leftover residual that is being
blamed merely by correlation is most cases in this hobby.
We can see how detrimental NH4 and NO2 are to aquatic
life. Extreme.

No doubt about it and this is why I'm used to state for well
cycled (fishless cycled) tanks..

NO3?
Almost non toxic by comparison.

Agreed..

The point?
KNO3 dosing/going above the target (which is bound to
happen), it far less cause for alarm or worry of poses a
significant health threat as many have historically
claimed , without testing or reviewing the research done I
might add

Well I do respect you to be a very engaged (natural)
scientist but "significant" does _always_ correspond with
statistical methods. Unfortunately I do know enough about
scientific ecotoxicity tests to realise that it's in my
mind not always that goal-oriented (target-aimed?) it
should have to be..

You should test what you __say__ before saying it. Common
sense. Then you discuss it and see what seems most
reasonable, then test that and so on...........

Well when I decided to enter my very first aquaria group on
usenet I made the decision to be a hobbyist only..

I often wonder all the things that are said in the hobby
and why folks claim authority etc, when what they say is
often shallow at best, and out right wrong at worst. So I
test to see. If I cannot show that, I propose an
alternative hypothesis that makes more sense given the
observations and go from there.

But aquariums are unique and multifactorial systems. How to
validate such results..? Statistical methods..?

I might never arrive at the ultimate truth or cuase, But
..........I will get a lot close than the folks caliming
things without even bothering to test them to see for
themselves.
NH4 can be add
NO3 can be added
NO3/NH4 can be added
Organic sournce of N can be added that are transformed
into NH4 first.
That way you can tease apart who's doing what and find the
real culprit.

Sorry I guess (my) life is too short for all that crap.. ;-)

I've been dosing KNO3 for 12 years, I've never seen any
toxicity until I got way outside the bounds of normal
ranges suggested.

I've no doubt about it but in a well set up (=stable) and
well stocked aquarium with a rich life of aerob,
facultative and anaerob bacteria 200 ppm NO3 would never be
a problem. In my mind probable effects (reduction to NO2)
of high ppm'ed NO3 were the main problem..!

BTW: Are you eventually "power filterer" and "vacuumer"..?

The research also supports that.
While folks are welcome to skeptism, they are also obliged
to offer support and an alternative to such skeptism, just
as I have done against such past advice often. Simply
saying it, belief etc does not make it so................

www.BarrReport.com

--
cu
Marco