It may sound silly, but maybe you can remove the 5 turbos temporarily, and 'borrow' something that eats snails, like a porcupine puffer. Know anyone in your area with a tank? Sometimes whacky solutions are your only option. DONT use any of the snail killing chemicals on the market, it will never come out of your rock and sand. I'd lend you Porky, but its a little far for me!