I have a new vivarium (new to me). It's a 30 gal. Oceanic cube with a false bottom pump which I presume operates the waterfall. My question is: There is another pump inside the stand with a splitter with two tubes. The tubes run up to the top of the vivarium and into it and drop down into the space where you add the water. I accidently dislodged the tubes and don't understand where they go.

If they just drop down into the water, what purpose would that serve? They would be like airstones. I can't contact the guy I bought it from who moved out of state. Can anyone help?