So I just installed the neo diffuser and WOW!!! What a difference! The bubbles are almost microscopic! I have to admit when I first opened the box and saw it in person, I thought “ there is no way this thing is big enough for my 90.” It’s a little less then an inch in diameter for the large size, rated for 30G and up. But man o man, this thing really puts out an amazing mist. I had to crank down my bubbles a lot. This diffuser puts out way more bubbles and such a smaller size than my previous 2in glass diffuser. Another plus is that I know this one won’t get dirty as it doesn’t sit inside a glass dish. There is no way for anything to collect on it, to clog it. So far so good! I’m very pleased!