I figured you would be more likely to see this here......
The debate about nitrifying bacteria rages on and on.....some people say that freshwater and marine bacteria are completely different and there are no overlaping bacteria. Some claim that they are one and the same species, able to switch from fresh to brackish to salt. Others say that the majority of the bacteria found, are either fresh or marine or brackish, but that there is a minority of bacteria that can withstand all the ranges. Me, well, I'm not a biologist, and I'm certainly not a micro-biologist, but the last option seems to make the most sense. (at least to me)
Regardless of what is actually true, if you keep switching back and forth from brackish to fresh, whatever bacteria are growing are going to get, at least shocked if not outright killed. Best to keep your levels steady and give it time.
If it was me, I would lose the UG....they trap too much detrius and you will have higher nitrates using one. Not only that, but it can be a pain to constantly clean the gravel so it doesn't clog, plus you have to occasionally put airline tubing down the uplift tubes to try and siphon out the gunk underneath there.
If you want good water movement why not simply buy a powerhead or two and aim them at the substrate?
