TPW Fermentation going on 3 weeks now

[riverdog]

Just wondering if it's normal to take so long. Started the TPW wash (with2 packets of EC1118) on 1/30/2019 starting gravity was 1.090 started bubbling the airlock within an hour and was going strong for the first week. However the SG is dropping rather slowly. Still getting a bubble on the airlock every 15-20 seconds. Checked SG a few days ago and it was at 1.025 and the temperature has been a steady 68, so it's going in the right direction, but why is it taking so long? Should I just let it keep going the way it is or should I add energizer? My other washes in the past, mostly fruit washes, never took longer than 2 weeks. Am I just being impatient?