Early termination of lease

[David Floyd]

I have a tenant that has been submitting maintenance requests nonstop since they moved in.  He now is complaining that duct system smells of mold and is affecting his health.  I had several AC contractors out to look at the ducts and I also examined them.  I found one area that is black but 2 AC contractors say it is just dust and mildew, not black mold.  None are willing to replace ducts in the summer.  Trying to determine what to do at this point.  I have a clause in my lease that states 

1. Termination In accordance with F.S. 83.56 &83.57, after one month’s rental payment has been received, this agreement may be terminated by mutual consent of the parties, or by either party given written notice of at least 15 days prior to the end of any monthly period. Any provision of this agreement may be changed by the Landlord in like manner. All parties agree that termination of this agreement prior to July 31, 2022 regardless of cause will constitute a breach of the tenancy as agreed on page 1 and all deposits shall be forfeited in favor of the Landlord as full liquidated damages at the Landlord’s option.

Can I lawfully execute this clause and terminate his lease early?  Will this be considered retaliation?  Should I get a mold test performed?