Originally Posted by mania
...spend the money on gym membership.
That is just great advice, really helpful, why didn't I think of that!
mtfunfloater, several people have noted proper set up and I agree your oars may be too long. You can cut them down if you decide they need it, it's not very difficult. It would be best to identify why they feel heavy. It may be fixable without adding weight to your oars or cutting them and if so I think most agree that would be best. Think about measuring your set up and if you can change things try that first. If you can't adjust your oar towers you could try adjusting seating position. Raising your set may help, especially if the oars are up at chest level when rowing, getting them down a bit can help with fatigue. With your oars set up with 1/3 in 2/3 out your still holding about 1/3 of the weight of the oar, more if your blades are heavier or if your outside the "optimum" set up noted above. If you really like your set up and just want to lighten the weight in hand of your oars, then proceed with one of the many suggested methods of figuring out how much counter balance.