How much is a lot? If you pick up a few bricks of the compressed and dried coco fiber bedding it will make a LOT of bedding once wetted and it expands. One brick filled a 40 gal breeder a few inches for me and that's a reptile tank where it is wider from front to back than a fish tank so that's a lot of area to fill.

Get a big Rubbermaid tote to put the bricks in, add the required amount of water, leave the entire thing outside for a few days, flip and stir it, and it will quickly dry out. You can also mix some cypress mulch in with it. Cypress also will not mold. Adding dried leaf litter will increase the mini eco system properties of it and you should never need to change it. Especially if it gets some spring tails or other tiny bugs (like what you see in your flower pots when you water them) in it.

It sounds like your new turtle is going to love it's new home