My car won't start due to battery?

My 95 honda civic CX i recently bought would start up fine, but the battery wouldnt hold much charge, if i hold the breaks while the car is off it most likely won't have enough power to start up, do you think this problem could be that there isn't enough battery acid in the battery? I refilled all the water ports and was wondering if the acid part might have to be done too, car runs fine after a jump, but the initiation to get it started without a jump is the problem. Please help, need to know if the acid could fix the problem even if its a 50/50 chance

Just buy a new battery, that would solve your problem

edit, you might want to check your alternator, that might be the problem as well