Manual pump

AN • will be having 2 babies about a year apart
I'm 10 days in to EP. It's going well and I've been blessed with a great supply so far. The hard part is pumping with my 12 month old running around. Since I came home with her sister, she's had a rough time adjusting and now she's getting her molars (my poor baby). Anyway, I've noticed that a manual pump empties me faster and I can do it without being hooked up to a pump. Does anyone know of this will hurt my supply? I'm trying to use it only when my one year old is around. Any thoughts? Thanks!