I had a very severe pesty snail problem in my 75 gallon heavily planted tank. Almost every leaf, my substrate and glass were covered. I no longer can see them!! It took about three /four weeks of placing a small 10 oz. plastic juice bottle (very firm plastic), punched with couple dozen holes (used nail and hammer). I placed a cucumber slice inside and a couple stones to hold it down. Every day I emptied 100's of snails from the bottle. Unbelieveable! I continued daily until I had no more visible snails. It has been two months. I cut back feeding. I have not noticed any snails. It worked!!! P.S. Make sure you put the lid on the bottle. I lost an albino cory who wanted cucumber! The snails can fit through a nail hole, just fine!