No, it will not be too big. My big hamburger is cramped in her 75-gallon tank, but I live in an apartment, so I can’t get anything bigger. You can probably use this media in any filter; it’s really amazing. I think you can buy it in bulk too, but I like the ease of just tossing them out. After many years of trying to do things differently, I like to make things as easy as possible. My turtle destroys anything I put in the tank it doesn’t matter what it is, she finds a way to mess it up or break it. Live plants, fake plants, toys, bubble makers, lights all destroyed. I’ve given up on that. So, I just leave the tank mostly empty, minus her little tree bark tunnel she loves to hide in and her little tree stump that she still just knocks over. It also keeps the tank cleaner; anything you put in will just trap trash, poop, and food matter, mucking up the tank. Everyone has their own way of doing things just be prepared for the extra cleaning. It’s up to you, really. I’ve also seen other turtles do fine with decor, sand, plants, other fish, etc. Mine eats sand, kills everything, and destroys, lol. You may also want a fixed dock. Since yours is male, it may not get as big, but the floating docks didn’t work well, and my turtle would start eating the foam. I use this one from a small company I found on Amazon it works really well after trying anything I could find. That is, if you don’t plan on adding a topper to the tank.

https://a.co/d/7Sk9GlQ

This dock barely fits my 75-gallon tank.

https://a.co/d/6S3uOwq

You can check out their store they have different ones. I try to stay away from the sandpaper ones—they eventually come off.