You are very welcome ! With tadpoles recommend keeping substrate bare since it's easier to vacuum clean when doing water changes. You got around 6 gal. in there so the hose could be something as small as aquarium airline if tads are tiny to avoid sucking them. With larger tads, that is not a problem and can use a standard aquarium gravity powered vacuum (recommend one with a start squeeze bulb). Since there is no filter, would change 25% of water daily with dechlorinated tap or bottled spring.