I love Aquaclear (Fluval) 70/300 and all the series, especially the 500/110. I would keep using it as it is hard to find better.
The is a very simple fix that will solve both of your problems, namely 1- the splash that has you annoyed, and 2- the excessive turbulence of the filter in a small tank. Best of all, it is free, and reversible (place it, or remove it).
In photo below (Fluval/Aquaclear 500/110), the cut-up soda bottle baffle. I challenge anyone to put a big Fluval 110 (with baffle) in a 10 gallon tank (yes, 10 gallon!), or in a smallish tank, and be successful with delicate plants or fish. . No problem of excessive turbulence! (I do not recommend the 110 in the 10 gal, that is just for kicks).
I did not invent this, somebody did years ago and shared it. I have been using it for years, in various 'local modifications' for specific purposes. By changing the width of the baffle, different flow patterns can be achieved. By covering one end of the 'roll', unidirectional (lateral) flow can be achieved. A marvel of ingenuity!