I set up a wall tank & have been fighting it since setup, it is about 24 inches long X 12 inches tall x 4 inches front to back. I have had fish tanks (both fresh & saltwater reef tanks) for over 40 years (yes I'm an ole man) & this one is my ultimate dream as it is on display as a centerpiece in my living room & lights up beautifully in the evening !
I did a fish less cycle using pure ammonia, tried some endlers & fought constant ammonia swings ! It is not the easiest tank to do water changes on, don't get me wrong, it is a nice setup, but daily (or twice daily) water changes fighting ammonia swings was not fun. It only holds 3 or so gallons of water so you just get the siphon going & you have to quit.
Anyways, I moved out the endlers & want it to be a low maintenance cherry shrimp tank. Now is were the questions start. Do I need to have a filter or airstone ? I have a very small filter in there now but it is a pain to get to clean, I'm afraid an airstone will cause water to splash (acumulate) on the wall & cause issues
I will keep the small filter/powerhead if I need to, but it sure would be nice if I didn't have to. I plan to have six cherry shrimp in there (3 gallon tank) I could easily do weekly water changes as I was doing them daily when I had fish in there. I also have some anubias nana petite in there as the pic below shows. I left the algae on the back wall for the shrimp to munch on Dan
the only downfall is they are kinda small at 1/2 inch, I have seen the enclosed glass ball years back & thought it was a gimmick. 
) 
Don't do anything...don't even siphon the coral dust in your tank...things will clear up on their own after a while. The less you mess with the tank, the better. 
