Question here is use the use of fresh pee or bagged urea, as opposed to aging the urine until it converts to ammonia (humonia) before adding to system. True, urea needs to be converted, but won't it simply be converted anyway if added fresh? Does it take longer? And even if it takes longer, once proper organisms are established, won't stability be achieved?
Also, bagged urea lists only N on the NPK. Does humonia contain more macro and micro nutrients than bagged urea?
Pat, I don't remember now the post you speak of, but I probably meant EC as in Electrical Conductivity, which is an important measurement for hydro growers. It literally is a measure of conductivity, which indicates how many salts are dissolved into the water. Pure water, as in de-ionized distilled water, does not conduct electricity. The dissolved salts, however, do conduct, and the more salts there are, the more conductive. The EC reading does not indicate what salts are dissolved, just how many in total are present. So, if a hydro grower mixes a bucket of nutes to say 1000 on his EC meter, and a week later the solution reads 500, then half of the salts have been used by the plant (or precipitated out), and it stands to reason to add enough salts back to replace what is lost. In practice, the reading often goes up, because more water may be transpired than nutrient used, and this concentrates the salts.
The whole notion of EC does not really translate to Aquaponics, because our nutrients do not begin as salts, but rather are products of biological actions. Typically, EC readings in AP are both misleading, and not important. You could, however, boost nutrient levels in an Aquaponics application using hydroponic nutrients, and an EC reading would at least initially tell you how much to add. That's sort of cheating, but it does work, especially with salt tolerant fish like tilapia, carp, trout, sturgeon and Sacramento perch.