Yes, you'll need to be able to test the pH to treat the problem, or to even know if there is a problem in the first place.
Depending on how much lime got into the tank and in what form, it may not have been enough to raise your pH to a level where you have to worry about it, but first you'll need a way to measure your pH.
Either with a meter or probe like mentioned above or with a chemical testkit.
If you can measure your pH and it is 8.5-8.6 or lower then don't worry about it.
If it's higher than that you'll need to lower it until it gets down into the range somewhere between 7.8 to 8.6
For a tank that size you can add half a cup of white distilled vinegar to drop the pH by about .2-.3
Add it to the sump and let it circulate for a few minutes.
Measure the pH again and repeat if necessary.
Btw, I probably don't need to tell you this, but if the lime was in powder form and is sitting in a pile on the bottom of the tank, siphon out as much of it as you can.
Luckily, it's only an overdose of lime and not the end of the world, but next time it may be a fatal chemical that gets spilled so it might be in your best interest to get all chemicals/suppliments (and even fishfood) put up in a cabinet away from little hands.