Backyard Aquaponics
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I'm sure the requested info is available in numerous places but I couldn't seem to find it. What is the best resource for finding out what the ranges should be and how to adjust them please?

Thank you very much.

Ideally you want no Ammonia or Nitrites. The toxicity of ammonia varies with the Temp and pH so here's a link to a thread that has a table showing you at what level, temp and pH ammonia becomes toxic - http://www.backyardaquaponics.com/forum/viewtopic.php?f=45&t=17298&p=402195&hilit=total+ammonia+nitrogen#p402195

pH should probably be roughly in the 6.5 to 7.6 range but higher and lower can work. I know I've seen systems running with at least 8.2 but there are usually nutrient lockout problems that have to be overcome.

Nitrates can range quite a bit without causing problems. In many systems a water test will show no Nitrates present so 0 would be the low end. This would indicate that the Nitrates were being used as quickly as they were produced.

pasting the table.... so it can be referred to [ it is variously posted within threads across the forum ].



[edit] basis for this is discussed here.... http://edis.ifas.ufl.edu/fa031

and this part way down in that document" in closed systems....nitrate will accumulate and may be harmful if higher than 250 mg/L."

note that ammonia can also inhibit plant growth... and ammonia toxicity in plants and problems with ammonia in nutrient solution is an increasing issue in agriculture and horticulture where overuse or residual levels of urea/ammonia based fertiliser forms occur. So the presence of ammonia is no good for your fish or your plants.

google "Ammonia and Plants" or better still "ammonia toxicity in plants".....

http://link.springer.com/article/10.1007%2FBF02185583 <<< effect on cucumbers
http://www.plantphysiol.org/content/35/6/820.full.pdf <<< beets and spinach (and barley grass)
http://www.sciencedirect.com/science/ar ... 3182900157 << tomato


** note the mention here about increasing pH from ammonia in solution.
(because ammonia solution is a base, so increase in pH can occur with elevated Ammonia and this affects trace element uptake and is detrimental to plant physiological processes)

http://www.gardenguides.com/131882-effe ... rowth.html


"...resulted in a very slow growth throughout the study. The leaves were
very small and light-green. The grain heads were short, often empty or filled with very few grains, which have
been recorded previously as typical symptoms of ammonia poisoning in grain crops"

http://www.pjoes.com/pdf/15.5/827-832.pdf

the following links also relate to these topics....

Ammonia - The Silent Killer > viewtopic.php?f=11&t=133
Nitrite and fish health > viewtopic.php?f=11&t=132

Nitrification process and stages > viewtopic.php?f=11&t=131

Salting for Fish Health (long thread) > viewtopic.php?f=11&t=3179&start=30


Good article about Salt and fish health... http://lilyandfin.com/wp-content/upload ... t_salt.pdf
(thanks Sam)

copied from post viewtopic.php?f=1&t=28000&p=546523#p546523

@JeffS - Nice chart. Never saw it explained that way. I think what the chart is telling you is that the lower the pH the less deadly the ammonia is because at lower pH levels the ammonia is more ammonium which isn't as toxic.

suspect so, though may also be partly due to the fish physiology as well (not sure).
Like all things that chart is a generalisation that abounds in the forum and was sourced from somewhere....
Similarly those numbers pop up variously over the web - some probably as pure plagerism (problem when sources don't stay attached to tables).

"lower pH levels the ammonia is more ammonium"
that relationship is definitely part of the situation...eg.
https://www.ysi.com/parameters/ammonia
http://web.utk.edu/~rstrange/wfs556/htm ... monia.html
http://edis.ifas.ufl.edu/fa031

[edit3] plus this has some information. http://www.dpi.nsw.gov.au/fishing/aquac ... ng-ammonia

[edit] fixed links... after 2 attempts

Example on reading and interpreting the TAN chart...

If I have an acidic system pH = 6.8 for example (blue squares)
toxicity sits at around 11ppm at 16 C , at 24 C it only needs to be 6ppm to be an issue.
so a cooler system provides a ammonia buffer of 5ppm.

Similarly for a pH 7.6 (Green boxes) - at 16 C <1.8ppm is OK but if water warms to 24 C then 1ppm is an issue.

And as you get pH around 7.8-8.2 then there is very little scope to carry excess ammonia.

the primary message is that things will be more forgiving with a lower pH and cooler water.
and that a system that is getting warmer can introduce issues if ammonia is present.

*but* fish tend to prefer pH around 7+ so it is not all simple....