[Chojin]

If you're doing 10 reps with the 50s, i'd increase weight, not reps. I only go over 10 reps on anything if I'm closing out a last set and want to be sure that I can increase weight the next time. Also, I'd use an 8-10 rep set in moderation (switch between 3-5 rep sets and 8-10 rep sets every month or so) or for exercises for which you are prone to injury (for example I've hurt my lower back 3 times now doing squats, so I no longer do 3-5 rep sets of those; an 8-10 rep set of squats forces me to use a lower weight to achieve the same level of muscle fatigue).

I've never seen a credible routine go over 5 sets, and most routines will have you doing 3 sets (with some exercises only needing 1 set, such as the deadlift). Lactic acid buildup is cumulative with either high reps or high sets and is the factor attributable to 'feeling the burn'. Neither a burning sensation nor soreness the day afterward is an indicator of a successful workout, so aiming for lactic acid generation through a high-set routine isn't really doing anything for you that a 3-5 set routine wouldn't.

Also it would be advisable to quit being a faggot and do compound exercises, preferably with a barbell (with certain exceptions where unrestricted ROM recruits more muscle fibers or prevents injury). I don't think you stated what it is you're doing with dumbbells, but I'm going to go ahead and assume you're doing nothing but curls, which is essentially the same as doing nothing at all. If you're just chasing a 'sick pump', pushups are a superior exercise and don't require any equipment.