My pump doesn't have a float. It has Contact Switches. Some pumps you simply 'raise' and 'lower' (physically) to adjust the water level.
I don't know about Ball Pumps. I haven't seen one. You can wait to see if someone answers here but be sure that's what you have. At worst, you can ctc the mfgr to see what they say, or you can bring it into a Plumbing Supply house and ask them. Maybe you can offer them a $5 tip or something. (I know - That advice is WAY more costly than the advice on this Forum.) :)
RE: Pea Gravel - That doesn't mean anything as far as water getting into your pump. It just means you have pea gravel. Do you now of the 'ground' UNDER the gravel is flat or slopes back towards the house??? That is the question. 10-4 on the gutters and mud-jacking.
RE: The Marsh - That could be but if your home was in a marsh or in a flood plain, it was probably built illegally by today's standards. 1) It probably wouldn't be allowed, and 2) if it was, you probably wouldn't have a crawlspace or basement BECAUSE of the 'ground conditions'. Yes, it's possible that the land was filled. You can check it out at your local Municipal Office to see what they know about the history of the land. I'm still a bit 'hesitant' to say your problem is marsh-related. (But then, again, I'm here and not there ...)
You could almost test the underground conditions by digging a 'hole' that's about the same depth as the pit somehere near the house out in the yard. After digging the hole, see if it fills w/water on a 'good day'. If so, then I'd be inclined to believe you're experiencing water collection due to the existance of a marsh (or something, but not an underground stream.)