I use the much maligned Combiplan with no leaks. I have say though, initially I did until I figured out the issue. You press the lid on thinking it is tight and secure, dribbles persisted. Because the lid is softer rubber it "grabs" a bit and doesn't really secure, water tight unless you apply a good deal of pressure all the way around. I do it by pressing the tank bottom to my chest, then working my fingers around the rim firmly press the lid against the rim of the tank. No leaks since and I do inversion agitation.