I bought a condo that was rehabed and they put a replacement tub over the older tub (I hate this type of shabby work). I have been here for 4 years and this year there seems to be a ton of water building up in between the original tub and replacement tub. Without tearing out the replacement tub, is there a way for me to drain this water and then seal this up so water does not get in between the tubs? I live on the firrst floor of this building, so I have a concrete floor and there is no leaking on the floor. I am assuming that the tub was not sealed properly, and I am hoping I can just loosen the drain to let the water out. I am not sure, so before I tear this up I am hoping someone can give me some direction.

I wish you would describe exactly what you have. I don't do work in condos so I guess I am dumb about the way you described a new tub over the old one.
I would like to know more.

It's a plastic replacement that is literally put directly over the cast iron tub. When you step into the tub you can feel the water in between the tubs. I am not sure how the water is getting in there, but it is and I know it should not.

Can I just unscrew the drain and let the water out? Do I need to literally take out the replacement tub?