Little spiral shaped snails you say?
Could be malaysian trumpet snails. Not known to eat plants, but to eat plenty of crap and algae. They burrow in the substrate and keep it aerated. They're quiet beneficial.
Snails get a bad rap in this hobby. I have them in my 55g and never see more than 2-4 of them at a time. My plants are fine and always have been.
Don't overfeed!!
Keep your tank clean like you should be anyway.
They will never get out of control, nor will they present any problem worth worrying about. The methods to rid the tank of them, as far as chemicals and tear downs go, are far worse than just keeping them.
In fact, I purposely introduced them into my 5g betta tank. It's all about knowing what you're doing.