Slow render and lots of noise

[tallbox]

So generally after maru's comment i edited almost all materials (ior and albedo)and light rays jump up from 0,8k to 1,6-1,8 mil.? Also i removed all lights with ies and scene was lit only with corona light as spheres.
I will try to improve more - to go above 2 mil.

[tallbox]

So here are an update of my process.
I re-edited scene and rays goes up to 2,5 mil.
I had a problem also with corona DR - all my slaves didn't want do render anything. I read almost every forum threads here and nfo files - finally slaves still giving me these ping errors but all they DO rendering job!

Regards,
G.