Exactly Chris, this is what I mean by testing yourself to determine the validity of industry claims for yourself. Anybody can make any claim. If it sounds reasonable enough then many just accept it as fact without ever testing it for themselves.
hotweldfire said:
Are nitrate kits (mine is a salifert) so unreliable as to be useless?
Yes, but chin up, here you go. If you want something useful get a test kit like this=>
DR 2800 Portable Spectrophotometer (Batteries @ £180+Vat, Not Included mate) Otherwise, forget about it.
These supposed Nitrate limits of 5ppm? Do you know where they come from? I can guarantee you that no one set up a series of tanks with shrimp, dividing them by various carefully controlled NO3 concentration and studied the results. That's not where that information comes from.
A lot of the data comes from widely available reports submitted by WHO (World Health Organization), USA EPA (Environmental Protection Agency) or Canadian CME (Council of Ministers of the Environment) data of testing done on North American streams, rivers and lakes. The values provided are all valid for fish native to these environments such as Salmon, Trout, Crayfish, Frogs - even on their food sources such as Caddisflies and Amphipods. So if you are keeping these species then yes, these are the limits that apply. But these numbers do not translate to tropical species. You cannot just lift a number from tests done in the St. Lawrence River and apply it to fish in the Orinoco River. Toxicity of any chemical agent is always species dependent.
hotweldfire said:
how do I judge the effect of nitrate (through ferts or through the combo of ferts and overstocking in my case) on my livestock?
Well, I mean, it's exactly as Chris says. How would you judge the effects of anything that you put in the tank or remove from the tank. As far as I can tell by your testimonial, you started adding ferts and have not detected any change in the behaviour, feeding habits, or colouration of the fish or shrimp. The only thing you mentioned is some test kit results which you knew, by your own admission, were going to be dodgy even before you tested. I don't see what more you need to do. You keep your tank and filter clean via regular maintenance, water changes and so forth, and the ferts that you add help the plants to produce an better environment in the tank than can be achieved without plants, so what more could you possibly ask for?
hotweldfire said:
What does a nitrate stressed shrimp/fish look like?
I mentioned this in the thread I linked to in my previous post. According to the studies, the main toxic action of nitrate on aquatic animals is the conversion of oxygen-carrying pigments (hemoglobin, hemocyanin) to forms that are incapable of carrying oxygen (methemoglobin, methemocyanin). So what does this mean? It means that the animal suffocates, so it should look very similar to mild CO2 toxicity. Are you seeing anything in the tank like this that is not directly attributable to actual CO2 poisoning??
hotweldfire said:
What are people's experiences of using an EI dosing method in a shrimp breeding tank? Is this a foolish combo? Should I revert to my ADA ferts (step 2 and k)?
CO2 and Excel kills a heck of a lot more shrimp than Nitrate could ever dream of. Ferts are not really an issue for shrimp. There is too much evidence to the contrary.
Cheers,