Several years ago many folks claimed excess nutrients caused algae
such as "excess" PO4 and NO3. I wanted to know how much excess it
would take for this to occur, so I added it to see(testing). Some
simple test can easily prove these assetions are patently false.

More recently, another group decided to claim that higher PO4 and NO3
are bad for fish. There are no PO4 toxic levels published in many
cases because it's virtually non toxic over the ranges ever
encountered by aquarists(say 10ppm or less).

Much like the algae testing of past, the claims are similar in their
arguement and approach for fish health. They make the hypothesis, but
they offer no back up support, no test, no primary research support,
no methods, nothing other than nice fuzzy words.

What has been published:

Pierce et al 1993 suggested for marine fish:
"Previous studies have indicated that long term exposure to nitrate-N
levels above 100 mg/L may be detrimental to fish(440ppm). This study
was undertaken to assess the acute toxicity of nitrate to five species
of marine fish, while efforts were taken to reduce the nitrate
concentration in the recirculating systems."

Marco 1999, suggests that warm water species have a suggested range of
"recommended levels of nitrate for warm-water fishes (90 mg N-NO3-/L)"

That's N as NO3, so 4.4X 90 = ~400ppm NO3.

Quite high.

here's a link to the common fathead minnow:

SETAC Journals Online - ACUTE AND CHRONIC TOXICITY OF NITRATE TO
FATHEAD MINNOWS (PIMEPHALES PROMELAS), CERIODAPHNIA DUBIA, AND DAPHNIA
MAGNA

Do the math for the conversion of N-NO3 to NO3 for ppms.
Quite high huh? Note the sensitivity differences for inverts, they are
much better test subjects than fish.

Still not convinced?

Well take a long look at the Fish and NO3 toxicity section in this
good review paper at table 3:

http://www.s2.chalmers.se/~tw/DOWNLO...ate_limits.pdf

It's fully assessible.

Remember to multipy by 4.4 to get NO3ppms rather than N-NO3!

As you can see, the ranges are extremely high and that warmer water
fish tend to have a greater ability to withstand NO3 levels as well.
When fish breed, this representst the behavior(positive good) and the
most sensntive life stanges(eggs and fry). I routinely have breeding
occur in such higher NO3 tanks(30-40ppm etc).

Now some have made claims that my advice concerning NO3 dosing is bad
for fish and they have not supported with test, with primary research,
nor applied plant tank experience neither over short term nor over
long term test.
I've done test with Ghost and amano shrimp and gone to over 160ppm
with ghost shrimp and Amano's before death occured. No fish where
adversely affected.

Now I ask them to stand before others to show their evidence rather
than preceptions to show and prove otherwise.

What I hear from:

1. Calims about less is better(but they rarely say how much less or
over what acceptable range, where the risk cut off is/do we gain for
maintaining a tighter control)
2. No supporting primary research(still waiting for one review)
3. Anecdotal advice and heresay from other web sites
4. Toxicity citations about humans, not fish
5. No toxcity test of their own to deny/confirm(they make claims/
critiques and then do not test their own questions to see if they are
correct)
6. Claims that behaviors change(how do we measure this?They offer no
solutions, reproductive is a good one I suggest)
7. Ability to set up a control tank and do a repeatable test.
8. Ability to breed and raise fry of several species of a fish in
their tanks.
9. Lack long term usage of the higher NO3 levels as they assume they
are bad and do not attempt them out of fear.

The burden of proof is upon the critic here.

I've done my job supporting my advice, spent the time testing, have
years of fish health to draw upon, the real question folks should ask:
have the critics done their job supporting their advice?

I just don't see it.

This is not personal, this is about the topic and getting an answer.
Not assuming less is better or that high levels are really bad or not
without first trying it out and seeing if that is the case, not by
circumstantial evidence(do you convict a poor innocent nutrient based
on circumstantial evidence alone?) or correlation alone, rather,
beyond a reasonable doubt.
They get irritated when I go after them about supporting their
position, take it personally etc, but the bottom line is not a
personal issue, it's about the fish, the hobby and the methods we use
the advice that is given.

I do not roll over and accept criticism when it's plainly wrong. I'll
still come back and pound the issue till they offer up evidence, not
personal remarks.
We look at the observations and facts, set up a test to see if our
hypothesis is correct or not, then make a conclusion.

I've done this.
I've provided strong background support.
I've supported my own hypothesis that higher levels are not
detrimental to fish or reproduction through testing.
I've repeated such test for years on many species that are supposedly
sensitive softer water species.
I've bred, as have many others, fish in such tanks.

Now mine you, I'm not going around suggesting that other methods and
advice are detrimental to fish or cause algae. These critics are
bringing this up all on their own. I have little issue with folks
supporting their usage of a method whatever it may be, but when they
malign the methods and advice I suggest in the process, I will defend
it.

When I defend the advice, some have suggested I am a bad guy, make
lots of personal asumptions about me(some are downright funny however,
they are really clueless about others and very assumptive) and am not
a nice person. Again using a personalization argument rather than one
that supports their position.
My personal life and aspects have no bearing here .........nor should
it.

This is about NO3 and fish/shrimp.


Regards,
Tom Barr