I have also received negative feedback about the resistance. After 15 minutes at the maximum level, you will feel that you are hardly putting an effort to row. However, this won’t be an issue if your weight is less. This could indicate an issue with the oil or gasoline mixture in the piston. Also, issues were mentioned by other customers with the footrests. They’d problem strapping their feet. It is a bigger issue as it becomes difficult for people who have small feet as the feet keeps on slipping. The footrest grip is not tight. This is affecting particularly when you would like to experience a workout without any interruption; when you actually want to go with the flow of workout. Fast rowing also becomes difficult with this type of problem as you have to stop and strap the feet back. However, the problem could be solved by using a wide and thick Velcro straps. Use your creativity and be resourceful while coming up with the ideas to solve the problem of slipping feet.
 The amount of water in the tank simulates the weight of the boat and crew, the more water in the tank the heavier the boat and crew. The standard Calibration Level is Level 17. If the user is lighter in weight, Level 15-16 can be used. If the user is heavier in weight, level 18-19 can be used. The maximum level to fill the tank is Level 19. DO NOT fill above the maximum level – this could void the warranty.
Handcrafted rowing machine with inchwater flywheel inch that replicates actual rowing feelFlywheel sits in enclosed water tank to ...provide smooth, quiet, self-regulated resistanceSeries 4 performance monitor tracks workout intensity, stroke rate, heart rate, and moreHandcrafted rowing machine with "water flywheel" that replicates actual rowing feel read more

The rowing machine itself is unlike any other on the market with its patented water filled flywheel. It is hard to exactly copy the action of a scull on the water, but the mechanics of the flywheel spinning in water comes in a close second on dry land. The fact that the water is 800 times denser than air means that there is no need for any extra resistance or dampening that you will find in normal air rowers. The faster you pull, the more resistance is generated giving it infinite variability. However, if you want to be able to practice rowing with a faster stroke, you will have to reduce the amount of water in the tank unlike an air rower where you just have to adjust the baffle.