. . . He does not seem to understand that I have a larger judgement against him and keeps demanding that I pay his judgment. . . . I will keep calling the court to find out what to do (?) . . .
Hold the horses. No one in the courthouse is going to offer any help! People around here get the mitten for trying.
If the knucklehead won't agree to crediting and foregoing his lesser judgment against yours, and you won't back off from yours, then you may have to seek assistance from a court. And the only way I can think of how to get a court involved is in the use of a declaratory judgment. Not in small claims, but at the next level. And not simple and not cheap.
But let me ask you something. You say you wish you had known about "compulsory counterclaims". Yet you must have known at the time you filed your claim that he had a claim against you and one that was apparently legitimate - ergo his judgment.
So what was your thinking when you filed knowing that he had such a claim and why did you not treat with it properly in your action?
Also do you know whether or not the guy is judgment proof? How do you rate the prospects of getting any money out of him? That could be very difficult, time consuming, troublesome, plus fruitless.
On the other hand he could garnish one of your tenants or a bank account, ending up with money in his hands while you have nothing but piece of paper. Seemingly he knows that and is the reason for the obstinacy. If it were me, I would consider discounting mine to a figure attractive enough for him to write his off.