Vorteil, because I want relatively clear water. My water always has this slight haze. Would love to not use a filter but then the water would just get very hazy within the following days. I just turn it on for about 2h a day. I get it it's not necessary but to my eyes it is. And the snails and Opae Ula can't eat the floating things anyway. Some run a filter. Some don't. There seems to be a division. As most of the time I use the middle ground
About the snails: Ok. That's what I thought. I will get 2 more trumpet snails because I want black ones too