Yes, it is a slow fill. I think it takes 36 oz to cover the film. Use NO MORE. The liguid has to move.
Lower the loaded reel in, pull up with a finger in the center. twist, lower, up& down once more. That is the first agitation. Now add the lid and small cap. Agitate by inversion 2/10 sec every minute. Hold it lid down long enough for the liquid to run into the cap, then rightside up. Repeat.
Pour out is far less critical so you can do the remaining steps with the lid on. Allow 25 sec for pour out.