How long to cycle a tank?

I have a 38 gallon tank that I just bought. Came with everything except fish. I filled it and have it running right now. I put Tetra Aqua brand Aqua Safe water balancer and Petco brand bacteria into the tank. I am running an Emperor 400 on it right now. The tank used to be a saltwater tank before I bought it from the gentleman that I bought it from, but now I have it set up for freshwater. So how long before it is cycled. I don't have any test strips. So I can't test the water.