Straight grain T&G Fir Floor Staining

Essex, Ct. I have just completed a resurface on a 7 yr old 240 sq. ft.exterior porch floor. It was well weathered some cupping of the 3/4 x 4 x 8 tongue and groove boards. It now is a new surface and the last step was to sand with a 150 grit disc on a 6" Rigid R/orbit sander. This floor is now ready for stain.
I am so glad I found your site as I was going to stain with Arbor-coat W/Base semi-solid stain but after reading so many -and + reviews I am not sure which stain I should use.
I just finished the porch ceiling with Defy Extreme on Fir Wainscoting,
very thin viscosity but it left a near natural color, as I wanted.
I was advised to use oil base stain by my B/M dealer but I fear the mold growth will be a problem as I had a black mold covered ceiling when I started.
I add Mildewcide additive in all exterior paints, can I do the same with stains.
Staining Monday morning 7/6/15. Please advise me.
Thanks for your great site will pass on to other painters.