Hello all !

Thanks very much for help. Now I`m rendering version without sun and is fine, standart settings but I change just super samples factory to 6
About MTL I read in manual and you right this is good method but here doesn`t work and I dont know why :/
I think
fenerolina got right and this is something from reflect like caustic etc ? But one thing is strange, why if render time is longer, scene is not noisy but is more dots around render and not just in this place :/
I change wall to RGB 205 and nothing :/
Whaat diffraction is turn off all time. here my settings:
Tomorrow I start new render with your settings and maybe will be good, because this is my nightmare

Today I spend all day for testing all settings. I change emitters, positions of sun and etc and nothing :p
I must fix that
Thanks
Piotr