RinoZ
The author is in the right here for choosing water magic. He is converting mana(Convertable molecules I assume) and binding them together barely to form water, if we assume he had taken earth he would have to procure more molecules for it to stick together and form a hard mass (spending more mana) than making a glob of water! and no he can't just use the mass around him and throw them around that's just using telekinesis to control it.