How much of a bioload do snails bring?

[Kytkattin]

Right now I have an overstocked 5.5 that does fine because of the lots and lots of plants I have. Even though I have a really good thing going, I want a mystery snail. Knowing full well I am at the brink of working well and everyone going belly up, I need to know just how much of an impact a snail is. It is equivalent to another betta? Gosh forbid, a goldfish?!? Maybe closer to a shrimp or two? Also consider that it is possibly a temporary situation for the snail as I will be setting up a 10 or 20 gallon in the next 6 months.

[paloverde]

Well, mystery snails can be very proficient poopers. You mention that your tank is already overstocked, perhaps it would be best to hold off on the snail.When you start up the 10 get your snail. This is just my opinion, I learned some very tragic lessons about overstocking in my childhood.

[Tikibirds]

what do you have already in the 5G?
mystery snails are poop machines. I think the minimum for the snail is 2.5 gallons but I find that without a filter, the tanks gets messy and the water smells bad in a few days without a filter. Not sure how plants would affect this