Ok, thanks. I'll try your suggestions and lets hope this will help. I'm trying to set the difficulty as high as possible so the traffic will be limited.
The hashrate is 900 H/s so to the diff should be between 40000 to 80000 ?
No. I really can't believe I am typing this, but, 900 x 20 = 18000, so that is the recommended low end for your difficulty, while 900 x 40 = 36000 so that would be the recommended high end for your difficulty.
I usually go for 30x my hashrate which nets me around 1 share every minute.