Deposit refund in CA

[Mahesh K.]

Folks,

My tenants lease runs out on Jan 8th 2017. On November 15th 2016, I notified my tenant that after the 8th of Jan, we will continuing the rental on a month to month basis but with an increased rent (effective January 15th).

The tenants decided to move out December 10th, providing only 20 days rent for December. The rental agreement states the following: "Should Tenants vacate before expiration of the term, Tenants will be liable for the balance of the rent for the remainder of the term, less any rent Landlord collects or could have collected from a replacement tenant by reasonably attempting to re-rent."

I know in CA, we are required to refund the deposit 21 days after move out. In this case, that date would be Jan 1st. If I am unable to find a replacement tenant by Jan 1st, what are the rules around the deposit refund? Thanks.