Have a call this morning where the complaint is that the caulking again and again breaks down along the bottom edge of the tub. She also says the tub moves slightly. Well there it is... How to secure the tub now? If there is an access panel possibly add mortar mix in key places that I can reach. And then I would normally used 100% clear pure silicone to caulk edge to floor.

Any ideas to secure this tub to the floor to stop the movement?

Is there one type of caulking best for this job?

Thanks for any suggestions.

We'd need to know where it is moving, specifically.

let's talk about the simplest problem and its solution.
just say the tub needs support under it.. i would squirt some expanding foam under it and immediately fill it with water. then apply a good grade of caulking.
i recently discovered dap 3.0 [www.dap.com] i am very impressed with its 'stickability'. it is not water cleanup so beware.

@ Packy

will be at Ferguson today. Will look for Dap 3.0
and I like the idea about the expanding foam too. Thanks.