hello; with such a gun my I assume you can check the temp directly of the pump motors, impeller assemblies and other parts.I also have checked them with my temperature gun I use for water changes.
You have other tanks which I again assume have power filtration. If the pumps are the same as the one in question then you can do a direct comparison. At any rate you can get some level of comparison as to the running temps. You might also check the temps of water coming into and then out of a questioned pump.