That is a nice new home for Took. I think it is fairly normal that he is hanging out by the filter, my guy when he rest likes to hang out by his heater. I bet he is going to love exploring his new home tomorrow after a nice rest. Bettas do rest or sleep at night and often will pick one area like Took has with the filter that they like to sleep in. They have a day and night cycle just like we do.
I would stop using the pimafix because it has oil in it and that can cause trouble with the organ they use to breath air with. Anything with the word fix in it is not good to use for Bettas. I think just the clean warm water will be enough for now but keep and eye out for any problems he is having and let us know if you need any help. I am glad you joined the forum and I hope you enjoy your time here and keep us updated on Took is doing.