I use bleach water once a week to flush out the jets and yet I still get these gnat worms often when I go to use the tub. I clean regularly and can't seem to get rid of them.please help me

I have to admit, in over 20 years dealing with insects and pests I have never heard the term "gnat worms." Please correct me if I'm wrong, but I assume you mean tiny soft-bodied creatures that you find in the tub.
Here are some pictures of fungus gnat larvae and moth fly larvae. Do either of these look familiar?