Sumiko Premiere Tonearm Drops Too Fast

Can anyone tell me if there is an adjustment to slow the speed in which the tonearm drops down onto the record? If there is no adjustment would anyone know how and where I would refill the resovoir with dampening fluid also is there any special fluid that I need to use. This is a Sumiko Premiere tonearm that I am using on a Thorens TD321 Turntable I would appreciate any help anyone can give me with this.