Join Date: Sep 2010
Location: West Hollywood, CA
First off, Dracaena, Spathiphyllum, ophiopogon, and Trichomanes are not aquatic plants. I'm guessing you bought them from those tubes they sell at Petco? Most of those plants are not true aquatics ): This might explain most of the trouble you're having. Put them in some flowerpots and get some other plants for your tank. Check out the Swap 'n Shop section here for tons of people selling and trading plants.
Second, for not having a CO2 system, you have too much light. With that much light and no CO2 you're going to run into algae issues. I had two T5HOs over my 36 gallon and I was told that alone was too much light. T5HOs are very powerful lights. Post a question in the lighting forum and someone should be able to help you figure out the best combination from what you have.
Lastly, the only way to get rid of the snails is to tear down the tank entirely and start over. If you just want their population controlled, use a combination of assassin snails, killing any snail you see, and trapping by lowering a piece of cucumber into the tank and then fishing it out once it's covered with snails. I've never done that but I hear it works well if you keep doing it.