Power Practice 
6x 1:30 work / 1:00 rest
Stroke Rate: 20
DF 126

Just hold the rate. That's it. Try to push the pace a little more each time, but just nail that 20 and go to work. Match or beat your previous split each round. I am pretty comfortable rowing at lower rates, with r20 being the sweet spot before my technique starts to degrade. I have a hard time not pausing at the finish when rowing at r18 or lower. Made too big of a jump with my split from round to round. Start a bit faster, around 5K pace (2:07.5) and improve by 1-2 meters each round for more of a challenge.