EMERGENCY! Paint Brush Fell into Water

So I walked in to the room with my 125g cichlid tank and the water was white as can be. Then I see a paint brush with fresh paint on it that my kids put in the tank. The paint is a white low VOC latex paint.

Not entirely sure how long it was like that. I would guess maybe an hour. I removed all of the fish and put them in my other tanks. I took out all of my porous texas holey rock and removed every and all ornaments and the sand substrate. Then I drained the tank completely.

I plan to just throw out my filter media(FX5) as well.

My main question is; How can I clean my FX5 and get it free of any traces of the paint for when I start it up again? Would running bleach through it then clean water do the trick or something different entirely, OR is that filter not good anymore?

Please help and thank you!