A couple newb questions: What is the purpose of using 2 shrimp vs 1? Any evidence that 1 shrimp is insufficient for >Xg tank? It seems to me unless you add a large number of fish right after the cycle (which is probably a bad idea in general, better to add slowly), part of the bacteria pop from even 1 shrimp's worth of waste will die back once you begin adding fish. I guess it depends on how much you plan on feeding your tank, predator vs non-predator tank, etc.
Second, thanks to advice on a couple other threads, the use of
LR and
LS means an additional cycle with shrimp is unnecessary. Uncured
LR will give you enough waste to get your tank started (using only cured
LR and you may have a working filter going off the bat without ever seeing a cycle). Again, as long as you add fish slowly, you should be fine. Opinions?
My newb understanding of all this is that tanks aren't really cycled or uncycled. Rather, a new tank is sterile - with denitrifying bacteria absent from your filtering media, and non-sterile - bacteria are present. The actual population size of this bacteria depends on the ammonia input to the system. While it can take weeks for sterile media to begin getting populated, the bacteria population will also take some time, albeit shorter, to respond to increasing ammonia input. This is why you might see a mini-cycle in a supposedly "cycled" tank when you add livestock (more correctly, add more food to feed the greater amount of livestock). Thus, the main point of adding shrimp is to provide an ammonia source during the relatively long period of bacteria immigration. Using live rock, you already have the bacteria population, and thus no need to provide an additional ammonia source of dead shrimp.
