I'm not really a water turtle person, but my 2 cents about filters is to get a canister filter. The canister sits outside the aquarium and suck water through a pipe into the filter, then back out into the aquarium. They work much better plus faster than the type you have there.
https://lovefishtank.com/100-gallon-aquarium-filter/
https://lovefishtank.com/100-gallon-aquarium-filter/