It's aquasource /f51b0034np
Loose where? If it is loose at the sink, where the whole faucet moves, you must tighten it from under the sink and you will most likely need a basin wrench. Go to the local hardware store and discuss this with the folks there. They should be able to give some better advice as I cannot ask questions. They will sell you the basin wrench and explain it's use as needed. Good luck!
