Thanks Ross, the more I can learn the better. Is this unit only for field testing? I ask this because all of our samples are mailed or brought into my lab. I never get out "into the field" to do water analysis onsite which is why we have opted for the "drop" method to date.
Also, do you have any opinions on the total ammonia that Greg and I were discussing (and yes Greg I am familiar with the nitrogen cycle)? I am aware of the two different types of ammonia present, but our Hach water quality test only gives results in total ammonia without the differentiation available (although the link I will post below gives us a way to aid in separating the two through pH readings and water temperature). I have researched some online this evening and have discovered some scientific documentation of kills resulting from high levels of total ammonia in ponds. When levels get over .8 ppm, ammonia penetrates the gill filaments. In high enough numbers this leads to vessel rupture thus allowing bacterial or parasitic infections to enter the bloodstream. Obviously this compromises the immune system causing fatigue and decreased feeding (flu like symptoms) and can lead to death. Of course the total ammonia is increased with higher densities of fish and feed, but other factors also apply.
I pulled an excerpt from a link I will post below. Very interesting and simplistic reading.
"Of all the water quality parameters which affect fish, ammonia is the most important after oxygen, especially in intensive systems. In small amounts, ammonia causes stress and gill damage. Fish exposed to low levels of ammonia over time are more susceptible to bacterial infections, have poor growth and will not tolerate routine handling as well as they should. Ammonia is a killer when present in higher concentrations, and many unexplained production losses have been caused by ammonia."
http://edis.ifas.ufl.edu/BODY_FA031 Thanks also to you ewest! Have you ever tried anything besides ag lime to raise your levels. Obviously the higher the total hardness and alkalinity, the better the growth with less stress on the fish. Gypsum and sodium bicarb. are other options from what I understand, but you might have a soil absorbtion issue you are dealing with (or extreme water exchange). Just throwing random thoughts out there!
Deb
