EWR Controller experienced a loss of wake turbulence separation when an A333 compressed to less than 4 miles behind a B757; the reporter indicating the Approach Controllers are not watching the speeds/separation on final.

Narrative

There was some compression on final on a marginal VFR day; ceiling at 1;500 broken. I had multiply heavy jets and a B757 on final. I had to constantly adjust speeds on final to make sure there was required wake turbulence separation. The Approach Controller was not giving enough room to aircraft following the heavy jets and the B757. I was not able to obtain visual separation due to the haze and low ceilings. This is what we have to do at Newark Tower; obtain Visual Separation; to avoid this. We are constantly getting planes 5 to 6 miles in trail of heavy jets with approach not realizing that the first aircraft must slow down; prior to the second one who is constantly gaining. So were not getting enough room behind heavy jets and B757. My situation was a B777 the lead aircraft; followed by a B757. The B757 was instructed to reduce 10 KTS to avoid loss of separation. A Heavy A333 was the number 3 and told to reduce about 10 KTS since he was going 10-15 KTS faster and gaining on B757. The A333 was later issued go around with separation of less then 4 miles. I was busy doing other duties and didn't send the A333 around in time which caused him to come inside of the 4 miles of the B757. This is life everyday at Newark we have to deal with doing heavy arrival times. We get slammed arrivals and make things work most of the time; obtaining visual separation/speed adjustments; etc. The Approach Controllers are not watching the speeds and separation on final.