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How big is your turtle? Pretty big maybe 2 in
How long have you had it? 2 weeks

What is the water temperature? 78
Did you use a thermometer? no
Are you using a water heater?no
How much water is in there? half of a 10 gallon tank
Are you using a water conditioner? no i change it
Are you using any filtration?yes

What is the basking temperature? not sure
Is there a basking light? yes
Is there a basking platform that is easy to climb on? yes but is too small
What kind is it or what is it made out of?foam its a floting onw
Is there a UVB light? yes

What have you been trying to feed it? krill and turtle pellets
When was the last time your turtle ate? dis morning

How big is the tank/pond/enclosure? 10 gallons
Is the tank near a window? no
Is the tank in a room with a lot of activity? my room

Have you read the Basic Care section? yes
Have you searched the forums for similar situations?yes
it stay under or on the side of the filter its acting really different from when i first got it

Without using a thermometer or heater, your water temps are probably cooler than 78F. Did your turtle eat everything? What kind of filter are you using?

I am confused.
Is this part of your earlier post? ( viewtopic.php?f=4&t=31892)
If yes - are you using a Zoo Med floating dock? the small are made for 10 gallon tanks. If he is too big for the dock, he is probably too big for the tank. I think you said you bought two more babies. Are they in the same tank?
Sitting and playing under the filter seems OK
If he has only been with you a week or 2 weeks he is still getting used to you.
If you added two new turtles while he was getting used to his new home, he could be getting used that now.
If this is part of your earlier post, it helps to keep adding to what you wrote so people can see all the information and can help you better.