Just wanted to announce and share a discovery that I have made over some time.
I have advocating the use of tree leaves, beech and oak in particular, over quite some time. People in Europe who have been keeping shrimp for a long time also use oak and beech leaves in their tanks quite frequently.
However, after hearing some reports from Germany that some shrimp species *mysteriously* stopped reproducing until the same individuals were put in a different tank and experiencing the same problem myself in my tanks with oak leaves in them, I decided to do an experiment.
I took out all oak leaves out of some tanks to compare the shrimp in there with the shrimp that still had oak leaves in the tanks. Surprisingly, the shrimp without the oak leaves started reproducing again! Also, the hair algae that was growing in those tanks *on* the oak leaves disappeared!
Also, I had been noticing that the shrimp populations that *were* reproducing in the tanks with the oak leaves were having trouble gaining numbers. Many young would die a couple of days after hatching and the young that survived would die right when they reached adulthood. The shrimp population was keeping stable but was not growing (another reason why I have not offered new species for sale yet...).
So...now I have taken out all oak leaves and things are back to normal. The shrimp are eating voraciously and most females are carrying eggs again.

So...now I am back to the basics. I have s plain sand substrate with a sponge filter and that's it. I feed fish food and nothing else (either pellets or flakes). I still think plants are fine, especially for nutrietnt export and additional "filtration", but the oak leaves have definitely gone out the window.
I will have to change my articlels accordingly to reflect this discovery (I updated my articles generally from time to time anyway so it's always good to check them periodically). This is what I love about this hobby. You can never sit down and say: "Now I know it all and there is nothing more to learn." There is ALWAYS more to learn, discover and more methods to pefect. That's what keeps things exciting.
Mustafa