under acid conditions how toxic is ammonia?

[Zander_The_RBP]

ive heard several times that under acidic conditions ammonia becomes ammonium and is not as toxic to fish what im wondering is when they say not as toxic how toxic is it ?

im asking this because im cycling my 150 gallon tank with 4 convicts i had in my 29 gallon. (go ahead flame me no store around here had pure ammonia) and my ammonia spiked to 4 ppm today and the convicts are acting completely normal! (my cycle is going really weird too first it was 1 ppm ammonia and 0.5 ppm nitrite then ammonia went down then ammonia went back up then nitrite disapeared but thats besides the point)

the ph of my tank is ATLEAST 6 (probably much lower as i did a 30% water change with tap water at 7.6 and it still tested 6)

so how toxic would it be with a ph under 6

 

[Lupin]

You can take a look at this table for ammonia toxicity.
http://dataguru.org/misc/aquarium/AmmoniaTox.html

 

[Zander_The_RBP]

wow thanks lupin ! that is a great chart

i also took anotehr look at my ammonia test under bright sunlight it is actualy 2 ppm not 4 so it looks like with my water at 80 degrees celsius and ph lower than 6.5 there is only 0.04 ppm of toxic ammonia in my tank

now im jsut wondering why my tank is cycling so funny the ammonia has gone up and down all over the place nitrite was up for a bit then went down and nitrate hasent shown up yet. is it my pH ? does having acidic water hinder bacteria's efforts to colonize a tank ?

 

[Bderick67]

Problem is that nitrite has the reverse effect. The lower the pH the more toxic nitrate is.

 

[Zander_The_RBP]

Problem is that nitrite has the reverse effect. The lower the pH the more toxic nitrate is.

really ? ive never heard of this as far as i know it is not the case. ammonia under acid conditions is chemically restructured into NH4 (from NH3) nitrite (NO2) does not undergo any chemical modifications under acid conditions.

 

[tcarswell]

Problem is that nitrite has the reverse effect. The lower the pH the more toxic nitrate is.

is the nitrite a typo ? Where can I read about this ?

 

[Bderick67]

is the nitrite a typo ? Where can I read about this ?

No I intended to state nitrite. I cannot find the article where I read this, thought it was on arofanatics. Anyhow there is no other sites or links that confirm this so my previously stated info looks to be wrong

 

[brianp]

"Ammonia" can exist in two forms in solution:
NH4+ (ammonium)
NH3 (ammonia) the most toxic form
If you lower the pH, you shift the equilibrium in the direction of NH4+ formation. So, less of the ammonia/ammonium is toxic.

Nitrite (NO2) is toxic because it binds to fish hemoglobin and prevents oxygen uptake. Essentially, the fish suffocate. I don't think (and I could be wrong) that the pH really effects the toxicity of the nitrite, per se. Rather, decreasing the pH may have some effect upon the permeability of the capillaries in the gills which may enhance nitrite uptake. However, I suspect that the primary reason why nitrite toxicity "appears" to increase with a decrease in pH is because the nitrosomas (?) vitality is diminished as the pH decreases and the oxidation of nitrite to nitrate slows. So, a decrease in pH causes the nitrite level to increase. Hope I didn't screw up this explanation.

 

[Jgray152]

^ You a biology teacher or something? You seem to know a lot about this type of stuff.

 

[Lepisosteus platyrhincus]

interesting. i have lower ph so this is good. not that i have an ammonia prob just that any that is created by the fish, is less toxic. sweet.