Dangerous Ammonia/nitrite Levels?

[splashtech]

Quick question here... if you guys had to put a 'cap' on the ammonia and nitrite levels, where would that be?

To expand on this a bit, I should explain why I'm asking. Basically I am creating a small web application which can be used for logging the various levels and whatnot. It will create graphs and keep historic data which can be drilled down into in the future. About the levels, I'd like to put in a threshold which if levels are recorded higher than, it flags it up as a problem (and gives a nice 'threshold' line on the graphs). Where would you put it? I'm thinking 0.25 for both of them? That's really a little on the high side isn't it, but not too much so, bearing in mind this is the 'oh no its really dangerous' line, not a 'ideal' line?

What do you think?

For nitrate, I'm thinking 40? Is that too high?
For pH, I'm thinking a lower limit of 6.8 and upper limit of 7.8. Reasonable?
For temperature, I'm thinking a lower limit of 23°c and upper limit of 27°c...? Perhaps 22 and 28?

 

[Smells a bit fishy]

Ammonia and nitrite yeh, both .25ppm. Nitrates I would say 80-100ppm but for discus much lower IMO.

Temp 22-28 and ph well that's a strange thing as some fish are meant to be kept at high temp. I think if you can do it 10% from a base point Ie your water. If it fluctuates more than 10% then there is an issue.

That's what I think but I'm still a newbie