If the pump in your turtles tank is noisy - it either needs cleaning out - or there is a fault with the pump itself. If the filter is clogged with debris - the pump motor will have to work harder to push water thought it - making it labour, and creating noise. If the pump is old, it may have worn parts which are either vibrating or rubbing against each other - causing friction.
If it just needs the filter cleaned - get into the habit of doing basic cleaning duties once a week. Wash the filter out in a little of the tanks water (NOT fresh tap water - as this will kill off the bacteria in the filter sponge !) Do a partial water change every week - to keep the turtles accumulated waste down to a minimum. Remember to clean the rocks etc when you do that.
Filter pumps don't last forever and will need the whole unit replacing periodically.
Turtles do have ear canals. however their hearing is not good, They are very sensitive to vibrations.
nooo??? why would it?
About a 20 gallon tank.
Depending on the species, one or two. Turtles will keep growing through their entire lives, overcrowding or expecting them to only grow to the size of the tank is something that usually leads to dead turtles.
I think it depends on how big the turtles are.
Tapping on the glass of the tank !
No, a mussel or clam cannot be put in the same tank as a baby turtle. Baby turtles, as well as adult turtles will eat mussels and clams.
Yes they will if they feel comfortable with their surroundings. They will but they must feel comfortable but its best to put him in a bigger tank with sand on it to make it more more comfortable.
The turtles will eat the fish.
You can just use regular water. In the summer/warm weather, I clean my turtles' tank outside with my hose. I also use faucet water. If you'd like to know how I specifically clean my turtles' tank, please contact me or reply to this answer.
Tapping on the glass of the tank !
no RES turtles are fresh water turtles