You might want to consider a dinner cruise, or more properly since you don't want to be gone overnight, a luncheon cruise.
In Tampa, the Yacht StarShip has a variety of cruises at varying prices. The sightseeing is primarily a ride around upper Tampa Bay around the downtown area.
The web site for the Yacht StarShip is
Yacht StarShip Dining Cruises
In the St. Petersburg/Clearwater area has Starlight Cruises, with two dinner boats and two others; one for sea animal viewing and one for dolphin viewing.
Starlight Cruises is at
StarLite Cruises - For a dazzling night out! Clearwater, St. Petersburg Florida
Years ago I did evening cruises on the Yacht StarShip and one of those in Clearwater, I don't recall which one. As you compare prices, some cruise prices include either a meal or a buffet but you pay for drinks, and others charge a price for the ride and have a separate menu where you pay for whatever you eat.
If this looks interesting to you, shop carefully. Also be aware there are other cruises available in the Daytona Beach/New Smyrna Beach area.
I recommended a luncheon cruise because you did not want to overnight away from home and it would be about a two hour drive at night from Tampa and even longer from Clearwater to come home if you did a dinner cruise. Lunch is also cheaper than dinner.
Whatever you do, Happy Anniversary.