I only use mini protanks now,have found no problems at all with them when running low,In fact I'll often not even notice they are running low until they start dry burning.
I have both the protank 2 & 3 along with a pro mini 2. I must admit from them all I get far less trouble with the mini than any other and just as much cloud. The only thing I don't like about the mini is it looks daft sat on top of my zmax.
I have a pro tank 2 mini & i find that it performs a bit like the evod tanks but it uses more liquid. Can't fathom that but it does.
Other than that i like it because when i take it all apart it's easy to get at all those little corners & clean it. I also have the protank 2 & i prefer the mini version of the two.